Need help (explanations) of a few BIOS configurations/settings

[Madcowz]

While tweaking the bios of my CUSL2, I came across a few things that I could not find sufficient (or none at all) information in the manual and tweak guides to determine optimal settings. I'll list them, and perhaps you can either explan there use or simply state which choice is for optimal performance:

Advanced settings:
OS/2 Onboard Memory > 64M choices: disabled/enabled
I'm using WinME; that's considered OS/2 right?

Advanced -> Chip Configuration:
SDRAM timing choices: set by SPD / user defined
I don't think iSPD is setting the optimal timings for my Mushkin Rev2 RAM which is running at 150MHz. It should be able to do cas 2 at that speed but I think the SPD sets everything to 3. I hear though that when you set it to user define and manually set to cas2 memory benchmarks take a HUGE plunge oddly... can anyone shed some light on this?

Video Memory Cache Mode choices: UC / USWC - (video card must support)
Using a Radeon, and I have no clue if it supports USWC; checked the manual and site, and still don't know. Perhaps if I knew what USWC was I would be able to guess what the Radeon uses.

SDRAM Page Closing Policy choices: One Bank / All Banks
Using Mushkin Rev 2 RAM

SDRAM Data Driving Mode choices: Normal / Strong

Command Per Cycle choices: Disabled/Enabled
Do you enable only if your using the onboard video?

Advanced -> PCI Configuration:
PCI Latency Timer choices: 0-255 (32 default)
I think lower for stability and higher for performance but I really have no idea... what's a good setting?

Advanced -> Shadow Configuration:
Video ROM Bios Shadow choices: Disabled/Enabled
Some sources such as the CUSL2 manual say enabling increases performance and many other sources disagree.

If you have any suggestions on any or all of these settings, please by all means share. There are many other CUSL2 owners out there and this would be beneficial to just about anyone interested in squeezing that extra little performance out of there machine.

 

[pm]

OS/2 is (was) an OS released by IBM... WinME is not OS/2

I've fairly certain that Muskin rev.2 is CAS3 as 143MHz or higher, but I'd need to check the chips on the DIMM with the datasheets. In any case, the SPD is programmed for factory certified operation. If you set it manually to a more agressive value, you are overclocking your RAM.

USWC is uncached speculative write combining... I'm fairly certain that I understand what it is, but it'd be long to explain. Suffice to say that it is better than UC (uncached). I'm not sure which cards support UCWC.

Latency numbers - lower is better... latency is the number of clocks you need to wait before something happens... the fewer clocks the better.

 

[Madcowz]

Actually they should yeild cas2 at about 155MHz which is amazing. I finally got mine to do cas2@150, but I'm having trouble getting it to do 5t/7t tras/Trc Cycle time. It freezes on boot at that speed so I have to keep it at 7t/9t

Anyone have any ideas about the other settings up there?

 

[pm]

What are the chip id's of the RAM chips on the DIMMs? We can look up the datasheet and see what the spec'd operation is.

 

[Madcowz]

Here are the chip markings:
0016PR
V54C365804VCT7

 

[pm]

So it's a 3.3V 8M x 8 SDRAM.

I don't think that they have the most up to date datasheets for this part at the Mosel-Vitelic website. According to this:

Link to PDF at Mosel-Vitelic's website

on page 12 (AC Operating Characteristics) line #2, the max frequency of the part in CAS2 mode is 100MHz and in CAS3 mode is 143MHz. This is probably out of date though - it seems to low and I notice that they don't have a T7 part on the list. Still, I can't imagine that the part is spec'd for CAS2 operation at 150MHz - this seems way too high. I still bet that it's spec'd for CAS2 up to 133MHz and CAS3 to 143MHz.

The 0016PR bit probably means "This is a production release part and it was packaged in Week 16 of the Year 2000".

Whatever... I was just curious.