VIA KT133A vs AMD760

[smn198]

A recent article on anandtech.com compared the VIA KT133A and AMD760 chipsets and concluded that DDR on a AMD760 chipset did not have significant performance advantages over the KT133A when using 266FSB CPUs. Here is what I have been trying to post to the anandtech articles forum but it seems to be stopping me?!?

I think the main reason that the VIA chipset looked so good when compared to the AMD760 with PC2100 is that the VIA used PC133 rates at CAS2 where as the PC2100 was rated at CAS2.5. If the tests were re-run with the PC2100 ram running at CAS2 (should be stable) then I feel that the significant performance advantage of the DDR setup would be shown. Although PC2100 ram is more expensive than PC133, PC1600 already sells for the same as PC133 and once more DDR ready motherboards are available, prices should fall. I also expect that once motherboards equipped with the AMD760 chipset become widely available, the price of these will also fall inline with VIAs offerings.

Toms article with CAS2 ram showed just over a 10% advantage with DDR under Quake3 where as Anand's review showed just over a 4% advantage with the DDR setup. Anyone else got any thoughts. Am I missing something?

<A HREF="http://www.anandtech.com/mysystemrig.html?id=1686" target="_new">System spec.</A> Ideas appreciated.

 

[Grizely1]

I agree. The people at anandtech are quite weird with their reviewing......

 

[HamsterSlayer]

I agree that difference in CAS latency is unacceptable, and I think it would make the DDR memory look a bit better if equalized.
Still, DDR RAM doesn't give that big a performance boost, but if you want to make sure you can wait a bit before you upgrade next time, DDR is what you want.

I think you should get a board with the AMD760 chipset, and then stuff it with PC2100 CAS2 DDR memory. Otherwise, you could just as well get a KT133A. Getting PC1600 DDR memory would be stupid, and you don't want PC2100 with CAS3 either. If you want a noticable performance increase, get the fastest. Otherwise, get PC133.


Sorry about the above....you weren't asking what to buy...were you???
My thoughts are these: The CAS latency should be equal for both types of RAM when doing a test . One should keep in mind that the reason DDR memory is not twice as fast as SDR is that the bandwidth is doubled, but the latency needs to be halved as well.
<P ID="edit"><FONT SIZE=-1><EM>Edited by HamsterSlayer on 01/06/01 06:44 PM.</EM></FONT></P>

 

[mpjesse]

I just wanted to point out that DDR was designed to bring higher bandwidth- not speed. Just like RDRAM. Clock speeds in memory kept getting higher- but the bandwidth sucked. Now that DDR exists, clock speeds can begin ramp up again and you'll see better performance.

Example: PC150 memory. Runs at 150mhz, but the bandwidth of SDRAM sucks- therefore it's not all that fast. Wait about 6 months when DDR memory clock speeds get higher and you'll see much better performance compared to SDRAM.

-MP Jesse