View Full Version : How much does disabling fast writes drop performance?

08-23-04, 01:58 AM
I am just curious since I have to turn it off to keep from 5 second freezes every 2 seconds. Completely smooth disabled just wanna know how much I am probably losing. BFG6800 gt

08-23-04, 01:58 AM
It will drop your framerate about 2% if even that

08-23-04, 06:59 AM
Results of a test i did when i first got my card.

6800GT ForceWare v61.77

3DMark03, Fast Writes OFF = 12780
3DMark03, Fast Writes ON = 12783

08-23-04, 08:09 AM
So what kinds of problems are likely to be caused by leaving Fast Writes on?

08-23-04, 09:17 AM
Most people have been experiencing a variety of issues, ranging from intermittent pauses during games to complete lockups.

08-23-04, 01:22 PM
On my rig, the exact opposite happens. If I disable fast writes, games studder and pause a little. If I leave it on, games are smooth. Must be a motherboard thing.

08-23-04, 01:32 PM
on mine if fast writes are disabled i lose around 600 points in 3dmark03. not a big deal but since i dont have any issues with fast writes enabled i leave it on.

08-23-04, 01:44 PM
i've been wondering about the same thing too. On my old motherboard (amd761) i could overclock my 6800GT to 400/1100 without problems with fast writes enabled, but since upgrading to an nforce3 board i could only reach 382/1100 with fast writes enabled. If i disable fast writes i can hit 400 easily, and my doom3 timedemo (1600x1200@HQ) jumps from 63.5 to 68fps. However, at the same time, with disabled fast writes but 18mhz more core speed, my aquamark drops from 60,800 to 60,500.

Disabling fast writes forces your cpu to write to the agp card through system memory, this will use up some of your memory bandwidth. Enabling fast writes let's the cpu write data directly to your agp card, saving on system bandwidth and i'd assume a tiny amount of latency.

I haven't any benchmark numbers for far cry, but far cry felt faster with 382 core with fast writes, than 400 core without fast writes. Yet the opposite is true for doom3 performance.

At the end of the day, it depends on whether your favourite games require sheer data processing power (higher core, doom3), or as much system bandwidth as you can give them (lower core + fast writes, far cry, aquamark).

Personally i'm sticking with a 382 core and fast writes enabled, but i only have single channel DDR at 440mhz, so system bandwidth is a commodity for me (sandra 2004 3150MB/s).

08-23-04, 01:49 PM
When I had a Radeon 9700 Pro, I had to turn off fastwrites to get any kind of stability. Seems they had an awful incompatibility with the Intel E7505 chipset (running dual Xeons here :) ). 6800GT runs like a champ though!