Memory timings or memory speed ?

pitsi

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I have the following question regarding memory, so I wanted to clear it up in my mind. I currently have 2 x 256MB Corsair PC3200 modules running at 2-2-2-5 (166MHz FSB), on my A7N8X Deluxe. Let's suppose that I wanted to upgrade to a P4P800 & Pentium IV 2,4C. I have seen many reviews, being able to hit 250MHz FSB with this processor, managing speeds of 3GHz. What memory would it be best to use in this case? Corsair has released today its new XMS 4000 memory modules so by using these, I would be able to run my memory sync with my CPU at 250MHz but using very moderate timings (3-4-4-8). Or would it be better to use my current memory at 200MHz (async) but with excellent timings? (2-2-2-6)

Which of these two options would give me the best performance?

I hope I haven't confused anyone but english is not my maiden language, so forgive me :)
 

FallOutBoyTonto

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IMO you'd be better off going for more speed instead of lower timings. The benefits of higher speed is a lot more then the mediocre performance hit of higher timings. Go for getting FSB and memory in sync.

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bum_jcrules

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Speed!

You will get many more millions of cycles per second and thus more page read/writes with higher frequency speeds than many more hundreds of cycles by better latecy settings.

Take your example. Say both ran at 3-4-4-8 and you shaved off the clcok cycles to 2-2-2-6. You are saving 1-2-2-2 for a total of 7 cycles per read request.

If you just increase the frequency by even 1MHz you will add 1 million cycles in the same timeframe.

So say you save 7 cycles x (X # of requests). You will not save 1 million cycles. Now you are talking about 50MHz.

Speed will do you best.



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TheMASK

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so theoritically, i wud see some gain in performance if i switch from DDR333 CL2.5 to DDR400 CL2.5 right?? i am running a KT400 mobo (A7V8X). right now i have 2 sticks of 256MB DDR333. my mobo as u guessed supports only one stick of DDR400. so i was thnking of getting a single stick of DDR400 512MB CL2.5.

I know its kind of irrelevant here, but i have posted in the memory section and did not quite get any info. so what do u suggest??

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pitsi

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In your case, the answer is no! What CPU do you use? I guess that you have a CPU that supports only 266MHz FSB so if you use DDR266, DDR333 or DDR400 it doesn't make any difference. They will all run at 266MHz since your memory needs to run at the same speed as your CPU's FSB. To be more specific perhaps you should let us know what processor you have.
 

bum_jcrules

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They are about the same results. THG did a comparison some time back.

With one you get speed and with the other you get bandwidth.

<A HREF="http://www6.tomshardware.com/motherboard/20030417/kt400a-05.html#gaming_benchmarks" target="_new">Here is that article</A>

You will see that with the same CAS Latency the extra 33.33MHZ pays of some dividends. Not much but there is an advantage.



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bum_jcrules

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That is not always true. It is a great rule of thumbs but you can sometimes get better performance with a faster memory bus.

Remember KT266A and KT333. Why was the KT333 a better board? It is the same here. In that THG article you can see that DDR400 single channel can give some really nice throughput to beat DDR333 on a single channel.

It is 6 of these and half a dozen of the other. Sometimes you just have to play with your settings to see what works the best. The same reasoning is behind higher latency timings and faster clock speeds.

See what works best and replicate that setup.

He has a KT400, the DDR400 is the best choice over DDR333. So if he wants to spend the money for a little extra performance it is not entirely bad.






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TheMASK

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Oh i forgot to mention my CPU. Right now i am running a 1700+ t-bred B overclocked to 2000MHz (12*166) with 2 sticks of 256MB (total 512MB) CL2.5 DDR333 RAM. Anything higher than 171 FSB and i get the BSOD. But i have run my system at even 207 FSB with a single stick and i did not run it long enough to see if it was stable at all.

So if i am getting the DDR400, i am going to make sure that i run my CPU at 200 FSB too. something like 10*200 or 11*200. I just wanted to be sure if the extra money on the DDR400 wud give me that much more performance at all.... in other words, is it worth it?? 10-15% increase in performance is worth it for me :wink: or may be even 5-10% is ....

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TheMASK

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tnx...ahem...BUM...ahem...JC RULES :wink:




<b>thinking of a good sig. till then...</b><P ID="edit"><FONT SIZE=-1><EM>Edited by TheMask on 07/16/03 03:33 PM.</EM></FONT></P>
 

bum_jcrules

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Movie quotes normally do well for sigs.

I used to use Steven Wright quotes like...

"I went to the store to by some batteries, but they weren't included, so I had to buy them again."

Now I just man handle <font color=red><b>dstell</font color=red></b> but I am sure that will wear off soon enough.


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bum_jcrules

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Much better.

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