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AGP USWC setting

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New Member
Nov 5, 2002
can anyone tell me if i can use the USWC(uncachable, speculative writing combination) with my radeon 8500? also what about the agp fast write capability?
asus p4s533
welcome to the forums m.d.

"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 (in the old article - The Phoenix Project) 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 not anything at all or even decrease performance."

fastwrites allows direct transfer of geometrical data from cpu to gpu omitting the system memory.

you can set it to USWC and run some benchmarks to check whether it does improve performance or not, most likely it wont influence anyway. but you can still keep it since its suppose to work better - if you dont notice any stability issues.

fast writes is known to cause huge instability.
im not sure if the 8500 has the support for it at stock, but you can also try to enable it and test it using 3dmark.
if it happens to give you lockups, you can still try to decrease the AGP interface to 2x and compare the results between: 2x, fast writes enabled; 4x, fw disabled.
that's about the concensus i've got from everybody.
I actually tested it on my old CUSL2/Geforce2 GTS setup and it made NO difference whatsoever in 3Dmark 2000 nor RTCW nor UT etc... Accordingly, I've left it disabled on my current rig.
I have the same motherboard and the same vid card and I'm using it without problems... I'd enable it unless it causes big problems