DDR CAS 2 and CAS 2.5 difference

justlam

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Hi, I am looking for new DDR rams and I came across PC 2100 DDR ram with CAS 2, 2.5. Did anyone ran benckmarks to test those two types of ram?

If there are Quake3 benchmarks @ 1024 x 768, that'll be better =)

Thank you in advance

Justin
 

bum_jcrules

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I don't have any benchmarks but it won't be much of a difference. You are only talking about half of one clock cycle. At 1/133MHz, 1 divided by 133,000,000 cycles per second, the diference is only 0.00000000752 seconds. You won't need benchmarks to show that you might get a few extra frames per second. (Over ~70 FPS the eye/brain cannot tell the difference anyway. Who cares if it gets 255 FPS nstead of 249 FPS.)

As Fatburger says - "Don't step in the sarcasm."

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"You don't feed a baby chile!" - Mr. Mom</b> :lol:
 

Tiberius13

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Well... 2.5 usually is run at 2.5-3-3 settings (each number refers to period of time the ram 'waits' at some point. The 2.0 ddr usually is run at 2-2-2 timings.

If you improve all 3 timings I have heard of people getting up to 7% performance improvements on their systems. The actual improvement for most people probably isn't quite that high, but don't take my word on it because I'm just passing on info I have picked up from un-audited sources.. :)

I have also heard it said that ddr @ 2-2-2 timings gives a similar boost to increasing a 133 fsb to 142 or so (with 2.5-3-3 ddr timings)... once again... I can't confirm or deny such information.

I think most people would agree that the faster timings give improved performance, but getting pc2400 or pc2700 and overclocking the fsb would give a larger performance boost (if the rest of your system supported it!)
 

justlam

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Oh ic...
would a DDR 2700 memory CAS 2.5 a better alternative than DDR 2100 CAS 2 in terms of overall system performance?

Justin
 

FatBurger

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Absolutely not, because no motherboard is going to actually run it at PC2700 speeds and use the bandwidth without overclocking.

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justlam

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Isn't the KT333 chipset suppose to support DDR 2700 ram?

BTW: if I run DDR 2700 (166mhz)CAS 2.5 ram @ DDR 2100 (133mhz), I will get CAS 2 speed right?

Justin
 

FatBurger

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The KT333 shows very little performance gain over a KT266a board. Via's 'non-a' versions have always been poor, the 'a' has always been the better chipset.

Cas2 is a setting in the BIOS. You can choose to set it at 2, 2.5 or 3, whichever you want.

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slvr_phoenix

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That is, unless you have my PC, in which case you can only hope that you never have to adjust your CAS settings. (Because there aren't any.) Heh heh. Poor Cel. He's an old beastie. I'd put him out to pasture except that I want to know that my next PC is upgradable. (I.E. I am waiting for both ClawHammer and Prescott to come out to decide on my next PC as I have a lack of faith in purchasing an Athlon or Northwood right now.)

<pre>If you let others think for you, you're the
only one to blame when things go wrong.</pre><p>