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Synchronize memory and fsb?

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August 10, 2007 12:08:39 PM

Hi all,

I keep hearing people talk about synchronizing their memory clock speed and fsb. Is this always worth it? I.e. If i'm running a Q6600 at 1333 mhz FSB, is DDR2-667 the best memory to use, or would DDR2-1066 give me a faster set up?

Thanks in advance for any help.

Matteo

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August 11, 2007 12:21:51 AM

The difference will be negligable, unnoticeable in games certainly. There are a few combinations of fsb:ram ratio and motherboard chipset that don't go well, but generally its not worth worrying about.
August 11, 2007 12:54:29 AM

If you dont overclock, DDR2 667 running stock is the best match possible without spending a fortune on memory. If you intend to overclock, then you would get higher speed memory that you can slow down so that it runs in sync with your FSB, then you bring your FSB up so that you get your memory back to its stock speed (and a little more ;) ). Higher speed memory is only good for allowing more overclocking headroom. Perhaps I have babbled too much without saying anything. This article refers to a core 2 duo, but gives you an idea still.

http://www.madshrimps.be/?action=getarticle&articID=472

EDIT: As you can see, running syncronous (In this case with DDR2 533) with the FSB provides higher performance than asyncronous until you reach a much higher memory speed, and even then the difference is negligible, and we are talking about gaming @800x600 here. I wouldnt bother with DDR2-1066 unless you are gonna OC a fair bit or you have cash to burn. DDR2-800 is going to give you lower performance than DDR2-667 unless you slow it down, so if you dont overclock AT ALL, get DDR2-667 and save money.
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August 11, 2007 12:58:08 AM

Generally you buy faster low latency memory and sync it with your FSB, DDR2 1066 cl5 depending on brand could theoretically be run at DDR2 800 cl4 or DDR2 667 CL3. The Q6600 has a FSB of 1066 MHz (266.5 MHz fsb x4) running sync (1:1 ratio) at stock requires DDR2 533. I have had better results overclocking the CPU and "down clocking" the RAM to match it. For your Quad running 1333FSB I would buy DDR2 800 or DDR2 1066, lower the timings, and run it at DDR2 667. Overclocking memory IMO is pointless unless it must be done to Sync with your CPU, due to the fact that you must usually raise the timings.
Having lower a latency instead of raw MHz speed IMO gives you a more stable and responsive system.
Many people buy into the hype of "high speed" memory and really have no idea how to take full advantage of its "speed"
August 11, 2007 2:41:24 AM

Hmm, that's interesting. Sounds like I've got a fair bit of reading to do, don't really understand what CL is or how it affects your system speed?

I think i'm going to buy some crucial ballistix DDR 1066, and hopefully that high quality RAM will let me do the kinds of overclocking you're talking about?

Thanks again
Matteo
August 11, 2007 3:15:14 AM

CL = CAS Latency (the amount of time or clock cycles that it takes to retrieve data from the memory module)

August 11, 2007 3:42:54 AM

Thus, lower CAS Latency is faster, but if you set it too low, you'll get system instability.

I'm in a similar situation as the original poster with RAM speed, I'm buying a Q6600, not sure yet whether or not I'm going to overclock. I'm leaning toward 1066 memory, simply because this seems like it'll give me the most options should I decide to overclock.

One question, my motherboard will be the Intel 975X "Bad Axe 2", I just want to confirm that the BIOS in this board will give me the option to run the memory at 533 (which I think is the "correct" speed if I dont do any over clocking, or 677, 800, 1066, and 1333, should I decide to overclock / push my luck.

Thanks for the assistance.
August 11, 2007 4:22:06 AM

I have a moderately overclocked Q6600 (see sig). I recommend running synchronously, it is faster and allows for lower CL and cheaper memory components.
August 11, 2007 5:37:47 AM

AARRGGHHH said:
Thus, lower CAS Latency is faster, but if you set it too low, you'll get system instability.

I'm in a similar situation as the original poster with RAM speed, I'm buying a Q6600, not sure yet whether or not I'm going to overclock. I'm leaning toward 1066 memory, simply because this seems like it'll give me the most options should I decide to overclock.

One question, my motherboard will be the Intel 975X "Bad Axe 2", I just want to confirm that the BIOS in this board will give me the option to run the memory at 533 (which I think is the "correct" speed if I dont do any over clocking, or 677, 800, 1066, and 1333, should I decide to overclock / push my luck.

Thanks for the assistance.


Why get the 975x "Bad Axe 2"? It is getting long in the tooth, with X38 "bonetrail" just around the corner you would be much better off for future upgradeability, fetures, and support.
http://www.bit-tech.net/news/2007/06/06/intel_x38_bonetrail_mobo_pictured/1
August 12, 2007 12:58:36 AM

AARRGGHHH said:
Thus, lower CAS Latency is faster, but if you set it too low, you'll get system instability.

.


Theoretically it's faster, but in reality its not always so..... having my ram run at cl4 on my P5B deluxe gives better performance at the highest stable frequency than the higher frequencies of cl5, and the lower frequencies possible at cl3, if that makes sense.
August 12, 2007 2:29:25 AM

i would suggest getting RAM one standard above the speed youre going to be running at to tighten its timings.
August 12, 2007 4:45:39 AM

I always thought that ddr2 800 would be better if you are not going to overclock, than 667. As evidenced by the last page of this benchmark test:

http://www.madshrimps.be/?action=getarticle&articID=472

Seeing that the ram and fsb would be running at a 3:2 ratio, rather than a 5:4 ratio. Correct me if I'm wrong please.
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