Shared mem between CPU and VGA. Try with PCI VGA.

Another possible issue is memory interleaving. I remember using an utility called “VIA interleaved enabler” back in the day and it gave me a noticeable boost on my S370 system. I think all VIA chipsets starting with Apollo VPX support memory interleaving but it’s often not enabled in the BIOS.

Memory Interleave disabled by default and no option in BIOS (a rather limited OEM mATX board) so I downloaded the patch from retronn.de and I'm installing it now.. Will report.

EDIT: Report: 4-Way Interleave enabled, and up to 144MB/s still abysmally slow compared to where it should be.. Maybe I should try a different stick of RAM? Could it really just be the onboard video cutting into the bandwidth? BIOS has no option to disable it, though I could boot from PCI (which means I will lose either my SLI or the network card..) Any other ideas?

EDIT2: Enabling DRAM Pipelined Burst took it up to 170MB/s which is still slow but something I can live with more comfortably.. According to benchmarks in 3D gaming the PC is about 15% slower than it could be 🙁 Any other ideas on what to turn on/off?

I think I now know what's wrong.

I tested the system with SiSoft Sandra and according to its benchmark the memory seems to be running at PC66, not PC100.

The problem is, even though according to the manual there should be a "DRAM Clock Select" option in the BIOS, it is missing in the latest (and only) version that has 32GB+ support. It defaults to Auto so I guess that's what it does now. Unfortunately, Auto seems to select 66MHz here.. Is it possible to edit the BIOS to put this option back in?

Also, could this be happening because I have PC133 RAM in there?

Could also be because of the stick of RAM being single sided.

I would try with a double sided stick AND with a PC100 stick.

Are you sure there isn't a jumper on the motherboard to select between PC66 and PC100?

What front side bus are you running for the CPU? What CPU do you have?

K6-2/400 at 100x4.0 by dip switches. No Tclk jumper. I will try double sided and PC100 RAM.

Double-sided or PC100 RAM made no difference. I can tighten the RAM timings all the way and I end up with a system running at around TX speeds (171MB/s) which tells me the DIMM clock defaults to 66MHz on this board for whatever reason..

The manual has an option for setting the DIMM clock explained in the BIOS section, but the BIOS I am on (latest) does not have this option enabled.

I really wish there was a way I could hack this option back in?

I will also use a discrete PCI card tonight to see if it makes a difference.. Not sure what to go for though, these are the 1995-1998 PCI cards I have:

Matrox Millennium
Matrox Mystique + Rainbow Runner
Matrox Millennium II
Diamond Stealth 3D 2000 PRO (Virge/DX)
ATI Xpert@Work (Rage Pro)

Doesn't matter, it's not the VGA performance that's relevant but the memory bandwidth the integrated core uses. If you don't use the integrated core, the full memory bandwidth should be available for the CPU.

dionb wrote:

Doesn't matter, it's not the VGA performance that's relevant but the memory bandwidth the integrated core uses. If you don't use the integrated core, the full memory bandwidth should be available for the CPU.

This is what I hope as well, if I disable onboard AGP VGA and default to PCI graphics I should probably gain more memory bandwidth.. I'll report once I check this out. I think I'll go with a Rage Pro PCI. This means I will have to go from Voodoo 2 SLI to a single Voodoo 2, but SLI with a K6-2 did not make terrible sense in the first place. I can use the SLI setup in another build, possibly move it to my Tualatin build to use alongside my GF4.

appiah4 wrote:

I really wish there was a way I could hack this option back in?

what about BIOS editing tools?

ATI Rage Pro PCI plugged in, BIOS set to PCI First and disabled Trident AGP card in Device Manager.

Result: Memory Read speed up to 237MB/s in Everest (vs. 260MB/s for K6-2 on MVP3 and K6-III on Aladdin V, so fairly respectable for a mATX OEM board).

I lost my SLI but I get almost the same speed @800x600 with a single Voodoo 2 now, so I have one extra Voodoo 2 to use in other builds, I am happy enough with this.

K6-2 400 is too slow to take advantage of an SLI setup anyway, so you're good to go 😀.