View Full Version : Source Engine very dependent on Ram speed?

02-14-05, 01:34 AM
I have done some testing and have found that the source engine is very dependent on the speed of your ram. The results below are based on different ram combinations on my backup machine using the valve stress test in CSS. I didn't know why my computer was running the game so slowly with the hardware I had. I thought well maybe if I pull out the PC2100 and only run the PC3200 stick I would get better results, I was right. (The weird ram speeds are because my mobo doesn't technically support over 200 MHz ram so I just pick what's stable).

Both tests: All high, reflect world, 4XAA and 8X Aniso.

Test 1:
P4 2.4A Northwood @ 2.9 GHz
768 MB RAM @ 242 MHz DDR (1x256 MB PC2100 and 1x512 MB PC3200)
6800 OC NU @ 375/750, 66.93 Drivers
Stress Test: 64.35 FPS

Test 2:
P4 2.4A Northwood @ 2.9 GHz
512 MB PC3200 RAM @ 375 MHz DDR
6800 OC NU @ 375/750, 66.93 Drivers
Stress Test: 87.90 FPS

All I did was pull out the slower stick of ram and it gave me a 1.5x boost in HL2 and Counter-strike source.

02-14-05, 02:32 AM
It is relativly mild on GPU, and more stressing on CPU it seems..
and, memory bandwidth is a big deal on P4 so..

02-14-05, 01:58 PM
Just curious, but why are your ram speeds so "different" than that of standard configuration ram?

242 MHz DDR
375 MHz DDR


02-14-05, 07:37 PM
The first speed is 242 because FSB was 121, the highest stable setting with my CPU. The second speed is because the board doesn't support PC3200 so I choose 333 as the speed and then OC the FSB. 333 + 21x2 = 375

02-14-05, 08:20 PM
anandtech has a good look at the differences in performance on a64 chips with memory speed, single vs dual, cas settings, and a look at size of cache. while your cpu is not an amd it may still be good to look through the article. kind of cool to see all of the differences. it seems as though hl2 is pretty tough on each component.

btw- your results seem very strange.

02-15-05, 12:47 AM
Could be that the PC2100 is a bad stick, but it went through memtest fine...

02-15-05, 01:36 AM
no suprise really doom3 was about the same someone played on 512mb pc2100 memory and it was really slow and choppy then he upgraded to 512mb pc3200 and it was a huge difference just the memory speed even if the memory size was the same.

02-15-05, 08:47 AM
But why are you running that PC2100 at 242 MHz? Just for the test perhaps? It should be at least 266 right?

02-15-05, 01:39 PM
But why are you running that PC2100 at 242 MHz? Just for the test perhaps? It should be at least 266 right?
He already explained. Its because of the overclock on his CPU.