Tip for increasing video speed

[LT.Homer Simpson]

Set the mode of the Video Memory cache to USWC(uncachable, speculative write combining).
Why --Enabling this feature will greatly improve video speed.

Note: An excerpt from an ASUS mainboard manual on Video Memory Cache Mode. USWC(uncachable, speculative write combining) is a new cache technology for the video memory of the processor. It can greatly improve the display speed by caching the display data. You must set this to UC(uncachable) if you display card cannot support this feature; otherwise your system may not boot. Configuration options: [UC] [USWC].

Note: BIOS settings on every Mainboard vary use this tweak as a guide.

1. Enter BIOS setup. When your PC boots a message will be displayed to enter BIOS setup. Typical keys to enter setup include F1, F10, delete and control S.
2. The Video Memory Cache Modem is usually listed in the Chip Configuration menu.
3. Set the option to USWC.
4. Save changes and reboot.

 

[Wargasm]

this works indeed .
tho it was enabled on the comp i tested at work did 1666 on 3dmark 2001 (yes onboard vidcard)

i set it to uswc and it did 1661 . prolly the results become greater on faster vid cards with more memory

this was an onboard 32 mb card

 

[Guest]

I put USCW on and used Freshdiagnose before and after to check its effects on my graphics card.

I got worse results for my Geforce3 ti500 with USCW on than i did with it off as these results show.

Before (off) After (on)

Random Pixels 966 400
Lines 87000 9666
Circles 23618 16779
Rectangles 157961 49410
Texts 1106029 775814
Flood Fills 5569280 934720
Draw 71884 52179

You can see an enormous drop in performance when USCW is activated, Can you see any reason for why switching it on shouldn't help me?

 

[LT.Homer Simpson]

UPDATE:


USWC or Uncacheable Speculative Write Combination improves performance for Pentium Pro systems (and possibly other P6 processors as well) with graphic cards that have a linear framebuffer (all new ones do). By combining smaller data writes into 64-bit writes, it reduces the number of transactions required for a particular amount of data to be transferred into the linear framebuffer of the graphics card.

However, it may cause issues like graphic corruption, crashes, booting problems, etc... if the graphics card does not support such a feature.

In addition, tests using FastVid have shown that such a setting can possibly decrease performance, instead of increasing it! This was observed with the Intel 440BX-based motherboard.

So, if you are using a Pentium Pro processor or a motherboard based on older chipsets, enable it for faster graphics performance. If you own a newer motherboard, you can try enabling it but make sure you run some tests to determine if this feature really improves performance or not. It's quite possible that it may do not anything at all or even decrease performance.

So this is one of those tweaks where you need to test both ways to see what is best for your system.