Does CAS Latency make a noticeable difference?

[bcoupland]

See Above.

 

[Wahsapa]

no, techincally your not suppose to be able to physically tell the difference between cas latencies. also, if the memory controller is on the cpu cas latency do close to nill for preformance, so it depends on what cpu you have.

 

[RockGuitarDude]

I agree. The performance differences due to CAS and what not are totally bull. The difference in a game is maybe 1 FPS if that from the worst ram to the best ram. Its a total waste and getting cheaper ram will allow you to get more of it. A gig of cheap ram will destroy 512 of expensive ram at almost the same price.

 

[nick1985]

no

 

[howdyduty]

Go with the 2x512 MB Samsung PC-3200.

Although, many shy away from CAS 3. CAS 2.5 is good though.

 

[araczynski]

agree with the above, problem with all these stupid benchmarks floating around everywhere for everything, people equate miniscule benchmark differences with huge real world impact, whereas its nothing more then free marketing material for the manufacturers.

i'm surprised i haven't run into floppy disk benchmarks yet, i'd have figured they're run out of everything else to waste their time with by now.

get a gig of stable memory and forget the expensive crap.

 

[So]

SEE my post titled CHOOSING YOUR RAM

 

[imported_Homerr]

I did some testing a couple of weeks ago:

I wanted to see the CAS timings of 2.0 vs. 2.5 on my system by pulling one stick out, then the other. My system also overclocks 10% easily. My wireless network and Norton AV were disabled during testing.

I currently have 2 x 512mb of RAM, but 2 different types:

Corsair XMS Extreme Memory Speed Series 184 Pin 512MB DDR PC-3200
Cas Latency: 2-3-3-6 1T
$118 currently

Taken from Corsair's website:

These parts support 2-3-3-6 latency on Intel platforms, and 2.5-3-3-6 latency on AMD platforms.

The other:

Corsair Value Select 184 Pin 512MB DDR PC-3200
Cas Latency: 2.5
$83 currently

System specs:

Athlon64 3000+ (2.0ghz stock, 2.2ghz OC'd)
Asus K8V Deluxe
9800 Pro
2x 36gb Raptors in RAID 0
1x 250gb Hitachi
1x 80gb WD800JB
Windows XP Pro


CPU-Z says on timings:

XMS (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
XMS (manual): 2-3-3-6-11-16 Manual settings in BIOS
XMS (manual, 2.2ghz): 2-3-3-6-11-16 Manual settings in BIOS, 10% overclock
Value Select (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
Value Select (manual, 2.2ghz): 2-3-3-6-11-16 <does not boot>
Value Select (auto, 2.2ghz): 2.5-3-3-8-11-16 Auto settings in BIOS, 10% overclock
Both sticks (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
Both sticks (auto, 2.2ghz): 2.5-3-3-8-11-16 Auto settings in BIOS, 10% overclock


Super Pi:
1m digits

44 seconds XMS (auto)
44 seconds XMS (manual)
40 seconds XMS (manual, 2.2ghz)
44 seconds Value Select (auto)
40 seconds Value Select (auto, 2.2ghz)
45 seconds Both sticks (auto)
40 seconds Both sticks (auto, 2.2ghz)


PCMark2004

3969 XMS (auto)
3980 XMS (manual)
4376 XMS (manual, 2.2ghz)
3970 Value Select (auto)
4343 Value Select (auto, 2.2ghz)
4003 Both sticks (auto)
4365 Both sticks (auto, 2.2ghz)


Prime95 version 23.8, RdtscTiming=1

XMS (auto):
Best time for 384K FFT length: 23.205 ms.
Best time for 448K FFT length: 27.830 ms.
Best time for 512K FFT length: 31.251 ms.
Best time for 640K FFT length: 39.571 ms.
Best time for 768K FFT length: 48.183 ms.
Best time for 896K FFT length: 58.325 ms.
Best time for 1024K FFT length: 65.528 ms.
Best time for 1280K FFT length: 87.700 ms.
Best time for 1536K FFT length: 104.800 ms.
Best time for 1792K FFT length: 127.801 ms.
Best time for 2048K FFT length: 143.805 ms.

XMS (manual):
Best time for 384K FFT length: 23.207 ms.
Best time for 448K FFT length: 27.864 ms.
Best time for 512K FFT length: 31.139 ms.
Best time for 640K FFT length: 39.546 ms.
Best time for 768K FFT length: 48.252 ms.
Best time for 896K FFT length: 58.220 ms.
Best time for 1024K FFT length: 65.705 ms.
Best time for 1280K FFT length: 87.544 ms.
Best time for 1536K FFT length: 104.530 ms.
Best time for 1792K FFT length: 127.201 ms.
Best time for 2048K FFT length: 143.515 ms.

XMS (manual, 2.2ghz):
Best time for 384K FFT length: 21.046 ms.
Best time for 448K FFT length: 25.207 ms.
Best time for 512K FFT length: 28.415 ms.
Best time for 640K FFT length: 35.923 ms.
Best time for 768K FFT length: 43.832 ms.
Best time for 896K FFT length: 53.056 ms.
Best time for 1024K FFT length: 59.610 ms.
Best time for 1280K FFT length: 79.703 ms.
Best time for 1536K FFT length: 94.932 ms.
Best time for 1792K FFT length: 116.111 ms.
Best time for 2048K FFT length: 130.992 ms.

Value Select (auto):
Best time for 384K FFT length: 23.137 ms.
Best time for 448K FFT length: 27.820 ms.
Best time for 512K FFT length: 31.245 ms.
Best time for 640K FFT length: 39.509 ms.
Best time for 768K FFT length: 48.135 ms.
Best time for 896K FFT length: 58.157 ms.
Best time for 1024K FFT length: 65.540 ms.
Best time for 1280K FFT length: 87.862 ms.
Best time for 1536K FFT length: 104.755 ms.
Best time for 1792K FFT length: 127.426 ms.
Best time for 2048K FFT length: 143.797 ms.

Value Select (auto, 2.2ghz):
Best time for 384K FFT length: 21.114 ms.
Best time for 448K FFT length: 25.386 ms.
Best time for 512K FFT length: 28.418 ms.
Best time for 640K FFT length: 36.036 ms.
Best time for 768K FFT length: 43.885 ms.
Best time for 896K FFT length: 53.074 ms.
Best time for 1024K FFT length: 59.671 ms.
Best time for 1280K FFT length: 79.667 ms.
Best time for 1536K FFT length: 95.146 ms.
Best time for 1792K FFT length: 116.107 ms.
Best time for 2048K FFT length: 131.284 ms.

Both sticks (auto)
Best time for 384K FFT length: 23.146 ms.
Best time for 448K FFT length: 27.803 ms.
Best time for 512K FFT length: 31.158 ms.
Best time for 640K FFT length: 39.435 ms.
Best time for 768K FFT length: 48.036 ms.
Best time for 896K FFT length: 58.165 ms.
Best time for 1024K FFT length: 65.504 ms.
Best time for 1280K FFT length: 87.564 ms.
Best time for 1536K FFT length: 104.516 ms.
Best time for 1792K FFT length: 127.068 ms.
Best time for 2048K FFT length: 143.468 ms.

Both sticks (auto, 2.2ghz):
Best time for 384K FFT length: 21.087 ms.
Best time for 448K FFT length: 25.309 ms.
Best time for 512K FFT length: 28.394 ms.
Best time for 640K FFT length: 35.896 ms.
Best time for 768K FFT length: 43.713 ms.
Best time for 896K FFT length: 52.946 ms.
Best time for 1024K FFT length: 59.577 ms.
Best time for 1280K FFT length: 79.624 ms.
Best time for 1536K FFT length: 95.084 ms.
Best time for 1792K FFT length: 115.647 ms.
Best time for 2048K FFT length: 130.551 ms.

Conclusion:

Corsair XMS and Value Select RAM perform more or less exaclty the same either at stock timings or overclocked. This is on an Athlon64, Pentium 4's probably would be different.

 

[nick1985]

nice fvckin post. :beer: for you.

 

[So]

Originally posted by: Homerr
I did some testing a couple of weeks ago:

I wanted to see the CAS timings of 2.0 vs. 2.5 on my system by pulling one stick out, then the other. My system also overclocks 10% easily. My wireless network and Norton AV were disabled during testing.

I currently have 2 x 512mb of RAM, but 2 different types:

Corsair XMS Extreme Memory Speed Series 184 Pin 512MB DDR PC-3200
Cas Latency: 2-3-3-6 1T
$118 currently

Taken from Corsair's website:

These parts support 2-3-3-6 latency on Intel platforms, and 2.5-3-3-6 latency on AMD platforms.

The other:

Corsair Value Select 184 Pin 512MB DDR PC-3200
Cas Latency: 2.5
$83 currently

System specs:

Athlon64 3000+
Asus K8V Deluxe
9800 Pro
2x 36gb Raptors in RAID 0
1x 250gb Hitachi
1x 80gb WD800JB
Windows XP Pro


CPU-Z says on timings:

XMS (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
XMS (manual): 2-3-3-6-11-16 Manual settings in BIOS
XMS (manual, 2.2ghz): 2-3-3-6-11-16 Manual settings in BIOS, 10% overclock
Value Select (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
Value Select (manual, 2.2ghz): 2-3-3-6-11-16 <does not boot>
Value Select (auto, 2.2ghz): 2.5-3-3-8-11-16 Auto settings in BIOS, 10% overclock
Both sticks (auto): 2.5-3-3-8-11-16 Auto settings in BIOS
Both sticks (auto, 2.2ghz): 2.5-3-3-8-11-16 Auto settings in BIOS, 10% overclock


Super Pi:
1m digits

44 seconds XMS (auto)
44 seconds XMS (manual)
40 seconds XMS (manual, 2.2ghz)
44 seconds Value Select (auto)
40 seconds Value Select (auto, 2.2ghz)
45 seconds Both sticks (auto)
40 seconds Both sticks (auto, 2.2ghz)


PCMark2004

3969 XMS (auto)
3980 XMS (manual)
4376 XMS (manual, 2.2ghz)
3970 Value Select (auto)
4343 Value Select (auto, 2.2ghz)
4003 Both sticks (auto)
4365 Both sticks (auto, 2.2ghz)


Prime95 version 23.8, RdtscTiming=1

XMS (auto):
Best time for 384K FFT length: 23.205 ms.
Best time for 448K FFT length: 27.830 ms.
Best time for 512K FFT length: 31.251 ms.
Best time for 640K FFT length: 39.571 ms.
Best time for 768K FFT length: 48.183 ms.
Best time for 896K FFT length: 58.325 ms.
Best time for 1024K FFT length: 65.528 ms.
Best time for 1280K FFT length: 87.700 ms.
Best time for 1536K FFT length: 104.800 ms.
Best time for 1792K FFT length: 127.801 ms.
Best time for 2048K FFT length: 143.805 ms.

XMS (manual):
Best time for 384K FFT length: 23.207 ms.
Best time for 448K FFT length: 27.864 ms.
Best time for 512K FFT length: 31.139 ms.
Best time for 640K FFT length: 39.546 ms.
Best time for 768K FFT length: 48.252 ms.
Best time for 896K FFT length: 58.220 ms.
Best time for 1024K FFT length: 65.705 ms.
Best time for 1280K FFT length: 87.544 ms.
Best time for 1536K FFT length: 104.530 ms.
Best time for 1792K FFT length: 127.201 ms.
Best time for 2048K FFT length: 143.515 ms.

XMS (manual, 2.2ghz):
Best time for 384K FFT length: 21.046 ms.
Best time for 448K FFT length: 25.207 ms.
Best time for 512K FFT length: 28.415 ms.
Best time for 640K FFT length: 35.923 ms.
Best time for 768K FFT length: 43.832 ms.
Best time for 896K FFT length: 53.056 ms.
Best time for 1024K FFT length: 59.610 ms.
Best time for 1280K FFT length: 79.703 ms.
Best time for 1536K FFT length: 94.932 ms.
Best time for 1792K FFT length: 116.111 ms.
Best time for 2048K FFT length: 130.992 ms.

Value Select (auto):
Best time for 384K FFT length: 23.137 ms.
Best time for 448K FFT length: 27.820 ms.
Best time for 512K FFT length: 31.245 ms.
Best time for 640K FFT length: 39.509 ms.
Best time for 768K FFT length: 48.135 ms.
Best time for 896K FFT length: 58.157 ms.
Best time for 1024K FFT length: 65.540 ms.
Best time for 1280K FFT length: 87.862 ms.
Best time for 1536K FFT length: 104.755 ms.
Best time for 1792K FFT length: 127.426 ms.
Best time for 2048K FFT length: 143.797 ms.

Value Select (auto, 2.2ghz):
Best time for 384K FFT length: 21.114 ms.
Best time for 448K FFT length: 25.386 ms.
Best time for 512K FFT length: 28.418 ms.
Best time for 640K FFT length: 36.036 ms.
Best time for 768K FFT length: 43.885 ms.
Best time for 896K FFT length: 53.074 ms.
Best time for 1024K FFT length: 59.671 ms.
Best time for 1280K FFT length: 79.667 ms.
Best time for 1536K FFT length: 95.146 ms.
Best time for 1792K FFT length: 116.107 ms.
Best time for 2048K FFT length: 131.284 ms.

Both sticks (auto)
Best time for 384K FFT length: 23.146 ms.
Best time for 448K FFT length: 27.803 ms.
Best time for 512K FFT length: 31.158 ms.
Best time for 640K FFT length: 39.435 ms.
Best time for 768K FFT length: 48.036 ms.
Best time for 896K FFT length: 58.165 ms.
Best time for 1024K FFT length: 65.504 ms.
Best time for 1280K FFT length: 87.564 ms.
Best time for 1536K FFT length: 104.516 ms.
Best time for 1792K FFT length: 127.068 ms.
Best time for 2048K FFT length: 143.468 ms.

Both sticks (auto, 2.2ghz):
Best time for 384K FFT length: 21.087 ms.
Best time for 448K FFT length: 25.309 ms.
Best time for 512K FFT length: 28.394 ms.
Best time for 640K FFT length: 35.896 ms.
Best time for 768K FFT length: 43.713 ms.
Best time for 896K FFT length: 52.946 ms.
Best time for 1024K FFT length: 59.577 ms.
Best time for 1280K FFT length: 79.624 ms.
Best time for 1536K FFT length: 95.084 ms.
Best time for 1792K FFT length: 115.647 ms.
Best time for 2048K FFT length: 130.551 ms.

That's awesome. Mind if I steal that for my thread (or better yet, if you post it there)?

PM me.