Isn't the one with Mosys chips a SGRAM model? That would make it faster in Windows / 2D stuff I think.

Godlike wrote on 2024-05-24, 17:19:

My choice have to be made between Gainward Riva 128 ZX and CardExpert which has Mosys. Which would you choose and why? I've seen also MoSys memory chips on Tseng ET6000 PCi which is great for DOS.

The ET6000 is famous for using a very special RAM type, that AFAIK has only been mass-produced by MoSys, the MDRAM. (multi-bank DRAM). These chips do not have a synchronous interface like SDRAM/SGRAM. I don't expect to find MDRAM on a Riva 128 ZX card. When the Riva 128 came out, MDRAM already wasn't a thing anymore.

The EliteMT (aka ESMT) memory chips are SDRAM chips. The chips on your card are rated for 143MHz memory clock at CL2 or 116MHz memory clock at CL3. Wikipedia seems to imply that the 128ZX supports memory clocks up to 125MHz, so the EliteMT card will either overclock the memory, or run at CL3, or run at a reduced memory clock of 116MHz instead of 125MHz.

The Riva 128 supports SGRAM as well, and Rawit is likely correct that the MoSys chips on the Riva card are SGRAMs. The photo is too bad to read the chip model number, but as SGRAM tends to be made for higher clock rates than SDRAM, it is lilely that these chips work at 125MHz with CL2, which will give a small edge of the EliteMT chips if they are operated according to their specification. While SGRAM also has some nice extra features compared to SDRAM, called "block writes" and "flash writes", these features are used for 2D fill operations with a solid color or repeating patterns only, so the "technology advantage" will only pay off in specific 2D GUI operations.

Rawit wrote on 2024-05-24, 19:11:

Isn't the one with Mosys chips a SGRAM model? That would make it faster in Windows / 2D stuff I think.

I am mainly interested in 3D performance. That's a good question actually SGRAM or SDRAM (RIVA 128ZX) which would be better in Win98 3D mode. Quake 2 or Unreal.
I don't know how to recognize SGRAM or SDRAM

mkarcher wrote on 2024-05-24, 20:13:

The ET6000 is famous for using a very special RAM type, that AFAIK has only been mass-produced by MoSys, the MDRAM. (multi-bank […]
Show full quote

Godlike wrote on 2024-05-24, 17:19:

My choice have to be made between Gainward Riva 128 ZX and CardExpert which has Mosys. Which would you choose and why? I've seen also MoSys memory chips on Tseng ET6000 PCi which is great for DOS.

The ET6000 is famous for using a very special RAM type, that AFAIK has only been mass-produced by MoSys, the MDRAM. (multi-bank DRAM). These chips do not have a synchronous interface like SDRAM/SGRAM. I don't expect to find MDRAM on a Riva 128 ZX card. When the Riva 128 came out, MDRAM already wasn't a thing anymore.

The EliteMT (aka ESMT) memory chips are SDRAM chips. The chips on your card are rated for 143MHz memory clock at CL2 or 116MHz memory clock at CL3. Wikipedia seems to imply that the 128ZX supports memory clocks up to 125MHz, so the EliteMT card will either overclock the memory, or run at CL3, or run at a reduced memory clock of 116MHz instead of 125MHz.

The Riva 128 supports SGRAM as well, and Rawit is likely correct that the MoSys chips on the Riva card are SGRAMs. The photo is too bad to read the chip model number, but as SGRAM tends to be made for higher clock rates than SDRAM, it is lilely that these chips work at 125MHz with CL2, which will give a small edge of the EliteMT chips if they are operated according to their specification. While SGRAM also has some nice extra features compared to SDRAM, called "block writes" and "flash writes", these features are used for 2D fill operations with a solid color or repeating patterns only, so the "technology advantage" will only pay off in specific 2D GUI operations.

Very helpful and informative. So you recon MoSys would perform slighly better in 3D Win9x ? So if riva 128zx chip support various memory types this subject is interesting perhaps possible candidate to choose faster memory and solder onto any 128zx. AFAIK memory mod works with Voodoo2 for example. Not the same kind of memory but same concept of modding for faster performance. I am curious will Riva128zx cards support both SGRAM and SDRAM or these are specific models accept one kind of memory each manufacturer of the card...

Godlike wrote on 2024-05-24, 20:26:

Very helpful and informative. So you recon MoSys would perform slighly better in 3D Win9x ?

I think it is likely, but not guaranteed. I neither know the specifications of the specific MoSys chips used on that card, nor know at what specifications the SDRAM on the EliteMT card is actually operated at. MoSys made both SDRAM and SGRAM chips, so there is no strict proof that the card uses SGRAM chips.

Godlike wrote on 2024-05-24, 20:26:

I am curious will Riva128zx cards support both SGRAM and SDRAM or these are specific models accept one kind of memory each manufacturer of the card...

SDRAM and SGRAM are connected the same way to the graphics chip, except for one pin used to control the "special features" of SGRAM. I expect most Riva 128ZX cards are built in a way that connects this pin to the RAM, but that extra pin is just ignored by SDRAM, or there is a removable 0ohm jumper link to interrupt that trace. On the other hand, I have no idea whether the BIOS knows whether it should enable the SGRAM features on the Riva chip, or it whether it probes for the RAM type by trying flash writes and checking whether they do what they are supposed to do.

While I claimed that the special SGRAM features are only used in 2D solid color or pattern fills, I completely forgot that most 3D rendering systems require a Z-Buffer clear per frame. Z-Buffer clearing also is an operation that suits the flash write capability of SGRAM perfectly, so SGRAM might also have a small edge in 3D games that make use of the Z-Buffer (AFAIK most do).

Still need to figure out which riva 128zx is the BEST (fastest in 3D) eventually modding, I can do soldering. I just don't know what are the fastest possible memory chips for riva 128zx. Or eventually bios update too.
Z-Buffer used in Thief: The Dark Project for example. Hopefully is there someone with riva 128 experience and testings behind. I appreciate your replies

I need to figure out how to recognise which is which Memory Type: SGRAM, SDR
Sgram seems to be better from what is written here.
https://www.vgamuseum.info/index.php/cpu/item … idia-riva-128zx

"SDR memory supports only in 64bit mode, so bandwidth is only 800MB/s."

Godlike wrote on 2024-05-25, 01:13:

I need to figure out how to recognise which is which Memory Type: SGRAM, SDR

Get a photo that is good enough to read the marking of the memory chips, then put the marking into a search engine to find a datasheet.

Godlike wrote on 2024-05-25, 01:13:

"SDR memory supports only in 64bit mode, so bandwidth is only 800MB/s."

If that's true, you definitely want to look for SGRAM-equipped cards. While I don't yet have an idea what technological limitation prevents the implementation of a 128-bit SDRAM interface on a chip that has a 128-bit SGRAM interface, it makes sense from a market perspective: If a graphics card manufacturer tries to cut down the cost of a graphics card by using SDRAM instead of the recommended SGRAM, it is very unlikely for that vendor to spend the extra cost of routing 128 data lines if the chip also works with 64 data lines. So it's likely that low-end card tend to use 64-bit SDRAM and high-end cards use 128-bit SGRAM. Putting extra effort into the chip design to support 128-bit SDRAM as well might be not worth the development costs at Nvidia.

There were tech limitations at that time: SDRAM chips had limited amount of pins, so for full 128-bit bus Riva 128ZX would need 16 chips.

mkarcher wrote on 2024-05-25, 08:36:

Get a photo that is good enough to read the marking of the memory chips, then put the marking into a search engine to find a datasheet.

Thats a very good advice. I will get better quality photos and search for datasheet to see which on i which. As far as I learn SGRAM could be more profitable for 3D in win9x.
That depends on research to find out more about memory chips on these cards. Still would be great to read a comment from someone already had experience with NV3 cards.
Thanks for help guys 💯

The Serpent Rider wrote on 2024-05-25, 09:01:

There were tech limitations at that time: SDRAM chips had limited amount of pins, so for full 128-bit bus Riva 128ZX would need 16 chips.

Do you think SGRAM support 128-bit bus and SDRAM 64-bit ? Sounds like a large difference. If this is true could be even more interesting to get both variants and compare them between each other
What in reality will be difference like significant or marginal. For example test in Quake, Unreal and syntetic benchmark like Final Reality or 3D mark 99

There were some rare Riva 128 variants with 64-bit SGRAM bus, but those have only 2 memory chips.

The Serpent Rider wrote on 2024-05-25, 09:01:

There were tech limitations at that time: SDRAM chips had limited amount of pins, so for full 128-bit bus Riva 128ZX would need 16 chips.

That's not completely true. 16-bit SDRAM chips were quite common at that time. You just need 8 16-bit chips to fill a 128 bit bus. Look at the card in the initial post: It contains 4 EliteMT M12L16161-7 chips on the front side. Each of these chips has 16 Megabits (2MB) with a bus width of 16 Bits. That's why there are two occurrences of the pattern "16" in the model number. So these four chips fill 64 bits of the Riva 128ZX. As these four chips already provide 8MB, there will be no further chips on the back side, and that card will have a 64-bit bus. So the pattern "SDRAM cards may have just 64 bit memory interface" may be a good heuristic at least, but as 4 chips can fill 64 bits, there is no reason you can not fill 128 bits with just 8 (EDIT: it used to say 16 here) chips.

Assuming the target memory capacity is 8MB, filling 8MB with 8 chips requires 8MBit chips with a bus width of 16 Bit. Possibly those chips do not exist, but clearly not due to "not enough pins", as 16MBit chips with a bus width of 16 Bit do exist. In fact, Wikipedia claims that the first SDRAM chips were 16MBit chips, and I have trouble finding 8MBit SDRAM chips, but I don't have trouble finding 8MBit SGRAM chips, for example the Hitachi HM5283206, which has just 8 MBit, but already 32 bits bus width. 4 of those chips provide 4MByte of graphics RAM at 128 Bit. Another example for an SGRAM chip is the NEC μPD4811650, which has 16 MBit, but still provides a 32-bit bus, so four of these chips provide the required 8MB at 128 bits.

In the end, it seems SDRAM is not that much focussed on providing small amounts of wide-bus memory as SGRAM is. The smallest amount of 128-bit memory I can assemble of 1996 SDRAM chips is 16MB. But it would not take 16 chips to that, but just 8 chips.

Yeah, I meant 8 chips. Which was not possible at the time.

The Serpent Rider wrote on 2024-05-25, 16:29:

There were some rare Riva 128 variants with 64-bit SGRAM bus, but those have only 2 memory chips.

very interesting.
I have researched now and find out that EliteMT is SDRAM and MoSys is SGRAM, find datasheet and learned from there. check this out

the question now which version will be faster in 3D running under Win9x and what would be % difference between one an another

mkarcher wrote on 2024-05-25, 19:59:

That's not completely true. 16-bit SDRAM chips were quite common at that time. You just need 8 16-bit chips to fill a 128 bit bu […]
Show full quote

The Serpent Rider wrote on 2024-05-25, 09:01:

There were tech limitations at that time: SDRAM chips had limited amount of pins, so for full 128-bit bus Riva 128ZX would need 16 chips.

That's not completely true. 16-bit SDRAM chips were quite common at that time. You just need 8 16-bit chips to fill a 128 bit bus. Look at the card in the initial post: It contains 4 EliteMT M12L16161-7 chips on the front side. Each of these chips has 16 Megabits (2MB) with a bus width of 16 Bits. That's why there are two occurrences of the pattern "16" in the model number. So these four chips fill 64 bits of the Riva 128ZX. As these four chips already provide 8MB, there will be no further chips on the back side, and that card will have a 64-bit bus. So the pattern "SDRAM cards may have just 64 bit memory interface" may be a good heuristic at least, but as 4 chips can fill 64 bits, there is no reason you can not fill 128 bits with just 8 (EDIT: it used to say 16 here) chips.

Assuming the target memory capacity is 8MB, filling 8MB with 8 chips requires 8MBit chips with a bus width of 16 Bit. Possibly those chips do not exist, but clearly not due to "not enough pins", as 16MBit chips with a bus width of 16 Bit do exist. In fact, Wikipedia claims that the first SDRAM chips were 16MBit chips, and I have trouble finding 8MBit SDRAM chips, but I don't have trouble finding 8MBit SGRAM chips, for example the Hitachi HM5283206, which has just 8 MBit, but already 32 bits bus width. 4 of those chips provide 4MByte of graphics RAM at 128 Bit. Another example for an SGRAM chip is the NEC μPD4811650, which has 16 MBit, but still provides a 32-bit bus, so four of these chips provide the required 8MB at 128 bits.

In the end, it seems SDRAM is not that much focussed on providing small amounts of wide-bus memory as SGRAM is. The smallest amount of 128-bit memory I can assemble of 1996 SDRAM chips is 16MB. But it would not take 16 chips to that, but just 8 chips.

Do you recon is riva 128zx SDRAM 64-bit bus and SGRAM is 128-bit bus variant? Seems like cards equipped with sgrams are better and faster, if this is true then how much % in benchmarks and games. Quake, Unreal or Direct3D.

edit:
I found some useful articles:
https://www.sharkyforums.com/showthread.php?2 … t-the-diference
https://www.neoseeker.com/forums/17/t491-sdram-vs-sgram/
https://arstechnica.com/civis/threads/which-i … ddr-ram.991519/

Which clearly says that SGRAM is better over SDRAM. "SGRam is a type of memory developed specifically for video cards. It was slightly faster than the speeds afforded by the older types of RAM types (EDO and early SDRam"
"SDRAM is Synchronous Dynamic Random Access Memory while SGRAM is Synchronous Graphics RAM designed specifically with graphics in mind. Always choose an SGRAM card over an SDRAM card with the same chipset eg; GeForce DDR SGRAM outperforms GeForce SDRAM"
just out of curiosity, anyone compared sg and sd variants of the same vga chip? doesn't have to be riva 128. but just curious of what performance boots in % I could eventually expect

Godlike wrote on 2024-05-26, 15:55:

Do you recon is riva 128zx SDRAM 64-bit bus and SGRAM is 128-bit bus variant? Seems like cards equipped with sgrams are better and faster, if this is true then how much % in benchmarks and games. Quake, Unreal or Direct3D.

For these two cards, be careful if the SGRAM card does not have memory chips on the back side. The chips on the front are 256k x 32 chips, which is 1MB per chip. So four memory chips visible in the photo are enough to provide 4*32 = 128 bits of memory bus, but only 4MB! While I can't find a datasheet for the MoSys chip, the -10 speed indication on SDRAM typically means that it can run at nominal performance (oftentimes, this is CL2) only at 100MHz, not at 125MHz, you would need the -8 speed grade instead.

Generally, a 128-bit bus is preferrable to a 64-bit bus, and I expect the difference caused by the bus width to be more significant than the different caused by the technology difference between SDRAM and SGRAM. Given that it seems you can't build a video card with less than 16MB video RAM and a 128 memory bus from usual SDRAM chips, I agree with the rule of thumb that any 8MB SDRAM-based card will have a 64-bit memory bus which is inferior to the 128-bit bus present on SGRAM cards.

For numbers about the performance difference, look into benchmarks published at that time, I don't know them - I just know how the the technology works.

mkarcher wrote on 2024-05-26, 17:23:

For these two cards, be careful if the SGRAM card does not have memory chips on the back side. The chips on the front are 256k x […]
Show full quote

Godlike wrote on 2024-05-26, 15:55:

Do you recon is riva 128zx SDRAM 64-bit bus and SGRAM is 128-bit bus variant? Seems like cards equipped with sgrams are better and faster, if this is true then how much % in benchmarks and games. Quake, Unreal or Direct3D.

For these two cards, be careful if the SGRAM card does not have memory chips on the back side. The chips on the front are 256k x 32 chips, which is 1MB per chip. So four memory chips visible in the photo are enough to provide 4*32 = 128 bits of memory bus, but only 4MB! While I can't find a datasheet for the MoSys chip, the -10 speed indication on SDRAM typically means that it can run at nominal performance (oftentimes, this is CL2) only at 100MHz, not at 125MHz, you would need the -8 speed grade instead.

Generally, a 128-bit bus is preferrable to a 64-bit bus, and I expect the difference caused by the bus width to be more significant than the different caused by the technology difference between SDRAM and SGRAM. Given that it seems you can't build a video card with less than 16MB video RAM and a 128 memory bus from usual SDRAM chips, I agree with the rule of thumb that any 8MB SDRAM-based card will have a 64-bit memory bus which is inferior to the 128-bit bus present on SGRAM cards.

For numbers about the performance difference, look into benchmarks published at that time, I don't know them - I just know how the the technology works.

I am interested in green riva 128zx at the very first photo of this thread. description says: CARDEXpert GW807 Nvidia Riva 128ZX - AGP 1x/2x - 8MB SGRAM Gainward Video Card.
photo is blurry so I can't see what are these mosys memory chips -10 speed or -8 speed grade (100MHz or 125MHz SGRAM)

edit:
I think Riva 128 zx can be modified. Even if Riva 128ZX with mosys sgram use 100mhz memory chips -10 speede grade then these chips can be desoldered and replaced with faster 125mhz chips -8 like occur on 3D Labs Permedia Diamond Fire GL1000 Pro AGP 8MB Video Graphics Card for example as donor card. I'll get my hands on it and try it out possibly. I need not to forget benchmark before and after to see the difference

Godlike wrote on 2024-05-26, 18:58:

I think Riva 128 zx can be modified. Even if Riva 128ZX with mosys sgram use 100mhz memory chips -10 speede grade then these chips can be desoldered and replaced with faster 125mhz chips -8 like occur on 3D Labs Permedia Diamond Fire GL1000 Pro AGP 8MB Video Graphics Card for example as donor card. I'll get my hands on it and try it out possibly. I need not to forget benchmark before and after to see the difference

Please be aware that changing from -10 to -8 SGRAM chips by itself does not make the card any faster. Using faster RAM chips probably allows the card to run at a higher clock, but you still have to set the higher clock! For that, you either need a modified BIOS, or a program (PowerStrip? RivaTuner?) that can modify the RAM clock of the card. The primary metric you can test is "how high can I increase the memory clock until I see corrupted graphics". Then you can run benchmarks to check how much real-world performance you gain by running the RAM at a higher clock frequency. Of course you also can compare nominal clocks, i.e. 100 vs. 125 instead of the maximum "reliable" clock. If you just want to compare the performance at nominal clock, you can always tune back to 100MHz even with the -8 chips installed.