Thanks for all your answers!
cyclone3d wrote:
On a side note, you can generally get a decent speed increase by getting more/faster SRAM as well a tightening up the RAM timings. I used to spend/waste tons of time messing with RAM timings and benchmarking back in the 486 days to get the every last bit of performance.
I have now played with the RAM timmings a bit and I'm now running 2-1-1-1 on the L2 which is the lowest I can go in my BIOS and also now with 0 wait state on my EDO RAM. Speedsys reports way higher RAM and cache performance:
My “stock setup” with 40 MHz FSB and 2-2-2-2 on L2 and 2 WS on my EDO gave me:
66,19 MB/s memory throughput (I am here referring to the number given by speedsys in the top left corner right under the CPU clock)
87,99 MB/s on L1
42,24 MB/s on L2
while the new settings give me:
92,11 MB/s memory throughput
92,64 MB/s on L1
55,1 MB/s on L2
However my speedsys CPU score only went from 57,67 to 57,68 which really isn't all to impressive. This all is with 32k TAG 15 ns and 256K L2 15 ns.
cyclone3d wrote:
You could also up the bus speed to 50Mhz and lower the multiplier to 3x. That will give you 150Mhz CPU speed, and the increase in bus speed will more than likely make up for the loss in CPU speed.
I also tried this and it gave my even better memory performance, even when I had to go with 2-2-2-2 on L2 and 1 WS on the EDO:
115,61 MB/s memory throughput
99,87 MB/s on L1
56,55 MB/s on L2
However my CPU score went down to 56,02. Interestingly my score in 3DBENCH 1.0c is with 98,4 at 50 MHz FSB still higher than my 92,6 I get at 40 MHz FSB. But since this is just an increase of ~7% I don’t think it is worth the increased stress on the system, because 7% on 15 fps won't get me any tangible FPS benefits.
cyclone3d wrote:The other option is to acquire a Pentium Overdrive chip. The PODP5v83 is the fastest that was made. It runs a 2.5x multiplier, s […]
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The other option is to acquire a Pentium Overdrive chip. The PODP5v83 is the fastest that was made. It runs a 2.5x multiplier, so at 33Mhz bus speed, you get 83Mhz, at 40Mhz you get 100Mhz, and at 50Mhz you get 125Mhz.
Edit: Here is a post that talks about overclocking the PODP5v83. 100Mhz may be doable.
They also mention the Cyrix 5x86-120, which is apparently faster than the AMD 5x86.
Pentium overdrive 83 MHz - overclocking options?
I don't have a POD, but I will surely pick on up just out of curiosity to see how it performs. I do own a Cyrix 100GP, which also runs at 120 MHz but I haven't tested on my current board yet. It doesn't support the CPU according to the manual, but maybe I will go ahead and just try anyway with this next time I'm in the mode for poking at the 486. Another thing holding me back is that I don't know which jumpers control the voltage and if the board can do 3,45 or 3,6.
BitWrangler wrote:You can use whatever RAM you like, but you're not going to get data into or out of a 486 faster than it's base clock time bus width, divided by 8 for bytes. Which is 160MByte per sec at 40Mhz... which is what decent speed FPM RAM with no wait states should be doing anyway.
That's a useful information. I didn't know the 486s BUS performance is so low. If that is true I really wouldn't make much sense to go bonkers with even DDR memory.
Moogle! wrote:Remember the video card can be a limiting factor too.
There are videos on Youtube of a 286 with a Diamond Speedstar 24x doing some impressive things. I think a good video card would let us see what the true limit of the 133Mhz cpu is.
I'm using a Matrox Mystic 220 so that shouldn't be a problem. System specs are btw:
AMD 5x86 133@160
QDI MP4-P4U885P3
32 MB EDO in on stick
Matrox Mystic 220
32k TAG 15 ns with 256k L2 15ns
and or cause floppys, soundcards and an sd card as a hardrive.
A couple of questions I do still have though:
- Will I get better performance with FPM RAM over EDO?
- Is there a reason/a way to go with 64k TAG and see benefits?
- Does anybody know of a real socket 3 board with SDRAM so I can go on a ebay hunt?
What I'm not interested in are SoC solutions like gdjacobs posted or a 486 core on a socket 7 platform like posted by nforce4max. I do own a couple of SS7 boards but my subjective definition of what a 486 is needs a socket 3 CPU.
Feel free to correct me or suggest anything else, I have given up on the DDR über 486 for now. Well maybe in 10 years when cost has been driven down significantly.