Ram speed question..

[ichabod]

Hi
I have overclocked my Q6600 to FSB=333 with normal x9 multiplier. I have OCZ DDR2 800MHz 4-4-4-15 memory. My question is: Should I set the FSB:memory ratio to 5:6 giving me exactly 800MHz or alternately leave the memory underclocked and use 1:1 FSB:memory ratio giving me 667MHz. This may allow me to tighten up the memory timings. I have heard there is a performance penalty for running at FSB:memory ratios other than 1:1. Which option is the best to go with?

Cheers
Dan

 

[Zeraphine]

Ur question is quite 'silly' frankly(no offense) you should always underclock the ram speed to be 1:1 with the stock FSB speed

ex assuming u got 800Mhz memory
FSB = 266 u should underclock ur Memory to 266

after that raise the FSB to 400 this will bring ur memory also to stock speed and the 1:1 ratio is always maintained and u get a 400x9 overclock

 

[Groveling_Wyrm]

Actually, the question was quite fair, and not silly. The only silly question is the question not asked.

Generally, you would want to run a 1:1 ratio fsb:ram. However if you can, you could try a better ram ratio. If you only go 1 step better with your ram stepping though, to 5:6, it could actually lead to a perfromance loss. Thus, in most cases, it is best to make at least a 2 step jump to 2:3, to see an appreciable performance gain. Some people have reported between 3-12 percent performance improvement this way.

However, since you have overclocked your cpu to 333, setting a 2:3 ratio would put your memory at 1000mhz. Your ram wouldn't be able to handle that. For your system as it stands now, your best bet for performance would probably be to stick with the 1:1 ratio.

However, you can tweak your ram and get better ram timings. Since you are running underclocked, you can tighten your timings a little bit, to eek out the best performance. Since you have good ram, you may be able to go with timings like 3-3-3-9-1T or 2T. It depends on your ram if you can get that tight though.


@Zeraphine - He will not likely reach 400mhz with that Q6600, unless he went with a multiplier of 8. Having a multiplier of 9 would put him at 3.6 Ghz. It is very unlikely that he has the setup required to reach that speed while controlling the temps.

To do so would require a top notch motherboard as well as a top notch processor and cooling. So far, only a few of the top enthusiasts have even been able to achieve that.

 

[Pride]

Be absolutely sure to use 1T ALWAYS instead of 2T! That's the biggest factor performance wise!

 

[Zeraphine]

@Zeraphine - He will not likely reach 400mhz with that Q6600, unless he went with a multiplier of 8. Having a multiplier of 9 would put him at 3.6 Ghz. It is very unlikely that he has the setup required to reach that speed while controlling the temps.

To do so would require a top notch motherboard as well as a top notch processor and cooling. So far, only a few of the top enthusiasts have even been able to achieve that.

I agree with u Groveling_Wyrm...i was just pointing out how he can get to his Original RAM speed with a 1:1 FSB DRAM ratio. yes its quite unlikely he can have a 3.6GHz stable overclock...and ofcource i think tightening the memory timings is appropriate unless he don't want to get a 3.2 GHz overclock with the multiplier at 8...i think his system can handle it..ofcource hell need a better cooler cause hell need to increase the Vcore...

 

[proof]

1:1 FTW! It gives you much less latency and you can tighten up your timings (most of the time). It also stops your memory from going through un-needed cycles while waiting for your processor which is communicating slower.

 

[ichabod]

Ok, thanks - sounds like I should go with 1:1 and try to tighten my timings. I may be able to push the FSB a little higher yet so the RAM underclock wont be quite so large.

I am a total noob to overclocking.. can someone tell me where in the bios of an asus p5k i can set the T1 setting - i cant see it anywhere.

cheers

 

[systemlord]

Ur question is quite 'silly' frankly(no offense) you should always underclock the ram speed to be 1:1 with the stock FSB speed

ex assuming u got 800Mhz memory
FSB = 266 u should underclock ur Memory to 266

after that raise the FSB to 400 this will bring ur memory also to stock speed and the 1:1 ratio is always maintained and u get a 400x9 overclock

People have been saying 1:1 is the best for long enough. Here have a look, please pay attention to the "read speeds" and the "latency".

 

[Zeraphine]

well ofcource systemlord when you have memory that can go up so high the DRAM:FSB ratio making performance bottlenecks gets thin.. but this guys RAM cant go that high unfortunately...but dont u see that At 1:1 the available memory bandwidth is almost completely utilized...but anyway u got a point...though in general im still telling that sticking with 1:1 ratio is the best idea as long as the FSB can keep up with the RAM speed...if u got some really fast RAM like say 1200MHz, Obviousely the FSB wont go that high with a 1:1 ratio and u have to use some other Ratio to do ur overclocking and to maintain the optimal RAM speed.