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8GB of DDR1 in a socket 939 system

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First post, by cdoublejj

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Reply 1 of 122, by raymangold

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2GB DDR1 modules have always been fascinating for a few reasons:
#1 DDR1 sticks in the 2GB capacity are always ECC buffered-- there are no 1 GB DDR1 unbuffered modules to my knowledge.
#2 DDR1 2GB modules (at least all of the ones I've seen) incorporate piggy-backed memory modules! So they are essentially two 1GB sticks combined.
#3 DDR1 outperforms early DDR2 modules-- and with some of the OCZ high performance sticks, you get some impressive timings.

Reply 2 of 122, by Unknown_K

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Interesting. I have a bunch of 2GB DDR1 RAM used in Opteron systems (Socket 940) that I will test in a socket 939 to see if they work (Opteron 180 chip).

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Reply 4 of 122, by cdoublejj

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You should really see this thread, as far as we know it's just this one specific set of ram on "E6" revision CPUs only that works. I also got no post with all 4 sticks with out, having enable the memory hole first. ( i cleared CMOS before installing)

I forget what page you want, http://www.overclock.net/t/293448/the-socket- … ebase-official/

you can look for post from "SEAFs" via "advanced search" at the top of the thread if that helps. Right now some of them are working on getting DDR1 4gb sticks working, if i'm not mistaken.

Reply 5 of 122, by shamino

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Tyan's support page for my socket 940 board actually lists support for one model of 4GB DDR333 module. Strangely there's only one model listed, so it makes me wonder if these things ever really materialized on the market, but apparently they certified one of them.
This was only at DDR333 though. At DDR400 the max they certified was 2GB per module.
I just checked and my 940 is using the exact same Qimonda part number as shown in the first post.

I'm a bit confused though, I thought the only difference between socket 939 and 940 was that 939 requires unbuffered memory. Apparently this 939 can also use registered? On my 940 registered is required.
I do remember reading some people whining about some Opteron steppings also being sold as Athlon64s. Maybe that's what's going on here? Can that same CPU also use unbuffered memory?

Reply 6 of 122, by Unknown_K

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Tried my Opteron RAM in a 939 MB, no dice. One great thing 939 boards have going for them is they can generally use high density 1GB DDR sticks the 754 systems refuse to work with (and all Intel DDR1 boards).

Since I still use XP on 939 boards or earlier 4GB of RAM (1x4gb) is more then enough for me, but the experiment was worth doing.

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Reply 7 of 122, by seaFs

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raymangold wrote:

#1 DDR1 sticks in the 2GB capacity are always ECC buffered-- there are no 1 GB DDR1 unbuffered modules to my knowledge.

True. Interesting fact: JEDEC specifies 2GB UDIMMs and 8GB RDIMMs. No manufacturer ever built them, though.

raymangold wrote:

#2 DDR1 2GB modules (at least all of the ones I've seen) incorporate piggy-backed memory modules! So they are essentially two 1GB sticks combined.

You've never seen the BGA RDIMMs, right? standard size as normal UDIMMs, but with 36 memory ICs. Samsung ZCCC, Qimonda CF-5 and some sort of Micron chips. The latest UDIMMs also used BGA chips, not TSOP. ZCCC might range to 270MHz, CF-5 even cracked 300MHz. I haven't found records about Micron BGAs.

shamino wrote:

I'm a bit confused though, I thought the only difference between socket 939 and 940 was that 939 requires unbuffered memory. Apparently this 939 can also use registered? On my 940 registered is required.
I do remember reading some people whining about some Opteron steppings also being sold as Athlon64s. Maybe that's what's going on here? Can that same CPU also use unbuffered memory?

AMD uses the same silicon for 939 and 940. The socket pin layout is just for the end user and to separate desktops from servers. RDIMMs have the same pin layout as UDIMMs. It's all a logical thing, nothing physical, so there are no additional pins necessary for registered support. Only ECC needs the extra 8 bit address bus width, and the older Athlon64s don't have that implemented.

Both Opteron and Athlon64 for 939 and 940 use the same dice. The important thing is the stepping of the CPU. The latest Opteron 1xx/2xx/8xx and Athlon64 X2 all use Rev E6 silicon. A tech review about the Athlon64 X2 (not the Opteron) mentions a 72bit memory bus, thus making it ECC ready. Wikipedia lists all the Opteron cores with E6, some with E1 (a stepping that never was available for dektops). I guess that the registered support for 940 is more of a BIOS thing. I'm not really deep into that matter to say what has to be programmed by the BIOS and what the CPU can program itself to recognize the memory. As for ECC, the BIOS has to be aware of this feature. As long as there is no ECC option in a BIOS, there is no chance to control it (because of 72bit bus width, the memory controller has to be programmed for the correct address width).

DFI boards don't work with RDIMMs, same with the MSI K8N Neo2 PE. The Asus A8N series mainboards all support this. Even the low-end A8N-E has an ECC option in the BIOS. At OCN we made some attempts to remove ECC from the DIMMs, but apparently that's not enough. Maybe high densitiy DIMMs aren't supported by all boards.

The final question is: Why should you use RDIMMs instead of UDIMMs? Well, because it is faster once you want 4GB memory. 4x1GB UDIMM requires Command Rate 2T, while 2x2GB RDIMM works with 1T. Don't underestimate the performance impact, especially in games (minFPS) and multi tasking (response time). Adding another 4GB for a fully populated memory array is just a logical step, because you can still run it with 1T command rate.

Reply 8 of 122, by Gamecollector

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You forgot something - RDIMMs are 1T slower in all reading/writing operations. In other words - CL is icreased to 1. This is the price for more chips on 1 DIMM.

Asus P4P800 SE/Pentium4 3.2E/2 Gb DDR400B,
Radeon HD3850 Agp (Sapphire), Catalyst 14.4 (XpProSp3).
Voodoo2 12 MB SLI, Win2k drivers 1.02.00 (XpProSp3).

Reply 9 of 122, by Half-Saint

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Impressive! Didn't know you could have 8GB of DDR1 on a normal desktop board 😀

seaFs wrote:

The final question is: Why should you use RDIMMs instead of UDIMMs? Well, because it is faster once you want 4GB memory. 4x1GB UDIMM requires Command Rate 2T, while 2x2GB RDIMM works with 1T. Don't underestimate the performance impact, especially in games (minFPS) and multi tasking (response time). Adding another 4GB for a fully populated memory array is just a logical step, because you can still run it with 1T command rate.

So you're saying that 4x1GB is slower than 2x2GB?

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Reply 10 of 122, by seaFs

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I know that RDIMM is slowed down, BUT just in addressing, not in data transfer (that would be the case with LRDIMM, which is DDR3 only). I did the benchmarks, I did the gaming and all that stuff with RAMdrives and VMs here on my PC, and 4x2GB is noticably smoother than 4x1GB.
The drawback of Command Rate 2T is that it heavily impacts write performance and access latencies. I somewhere read about the problem with DDR1 and Command Rate 2T, but don't know where. The problem was that 2T hinders further memory addressing in certain conditions and thus impacts all the accessing and data transfer, because several hundred (!) wait states occur. This mess was cleared up with DDR2, which explains why there is not such a big performance impact when switched to 2T (and that's why most DDR2 is specified for 2T, because it mostyl doesn't matter).

Read throughput is almost the same in Aida64 memory benchmarks, independent of UDIMM 2T or RDIMM 1T

There is one particular test scene for me: Borderlands 2, when encountering the final boss. This is heavily CPU limited for a very short time. The boss suddenly shows up and with 4x1GB I have a huge FPS drop that makes the game hang for half a second, but with 4x2GB there is just a very slight stutter.

This was my setup with 4x 1GB OCZ PC3200 Platinum EB sticks. The DIMM pairs top out at 265MHz and 275MHz at CL3, respectively. With CL2.5 245MHz was possible.
I could'nt get it stable above 235MHz. Notice the big drop in write performance, which is two third of read performance. The latency is not that good, too. When scaled up to theoretical 250MHz, you'd get 65ns latency with the same timings.
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Now the RDIMMs. After some hardcore tweaking they ran at 250MHz. If my CPU wasn't that bad, they might run at 267MHz as well.
Here the write throughput is as it should be: higher than read performance. This is the same behaviour with UDIMMs, somehow the Athlon64 can write more than it can read. Also have a look at the access latency, which is at 61ns, so theoretically 4ns faster with worse CL.
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Phew, found another screenshot of my testing phase, shortly after I purchased the RDIMMs.
It's the same setup as with the UDIMMs, 233MHz, CL2.5. Now check this out and think for yourself 😁
This is a whole different world.
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Last edited by seaFs on 2014-09-03, 09:05. Edited 1 time in total.

Reply 12 of 122, by seaFs

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40€ is way too much. I got mine for 20€ + shipping.
These are Qimonda DIMMs. The Label reads the following.

Qimonda HYS72D256320HBR-5-C
2GB,DDR,400,CL3,ECC,Reg

They use Qimonda CF-5 memory ICs and get very hot when running 250MHz. Better have some active cooling for the RAM.

Reply 13 of 122, by Half-Saint

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40€ including shipping is not that much for 4x2GB considering 1GB modules sell locally for anything from 7.5€ up to 15€ each! Yeah, the local market is screwed up that way.

Also not interested in overclocking.

Can you post pictures of your modules? Thanks.

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Reply 15 of 122, by cdoublejj

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Half-Saint wrote:

Well looks like you can get this type of ram for next to nothing. Could pick up 4 sticks for about 40€ which is dirt cheap.

After looking on eBay for a small while I picked up 7 sticks for $14 USD shipped! 😀 😊 It is indeed common and cheap. Now I need to find an SSD or something and a video card.

I hear the new SSD can take the punishment of not having AHCI better than the old ones. Some have said Raid might restore AHCI functionality but, requires 2 drives.

Reply 16 of 122, by Half-Saint

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Wait you mean you picked that up now or recently? Because there are lots and lots of them being sold for way more than that.

The cheapest I could find is $35 + shipping for 6x 2GB. Would probably end up paying another $35 for shipping to Europe.

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Reply 19 of 122, by cdoublejj

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Half-Saint wrote:

Here's a nice one:
http://www.ebay.com/itm/QIMONDA-HYS72D256320H … =item19d8e49d2d

$25.99 + $38 in shipping for one module 😀

that looks like 25 bucks for just 1 stick. OUCH! Man and you have to pay an arm and leg for shipping.