ddr333/ddr400 fsb266 fsb333 what a mess????

[rich110]

I have been going thru some site about new motherboards and I get totally confused :

Let's take AMD for example :
Some products claims to have an FSB of 333 and they have to use DDR400, should it be good enough to use DDR333?
FSB266 would use DDR266, which has been always the case in the past. What has messed up now?


P4 :
for FSB400, we should be able to run them using DDR200 or SDRam-100 (which is quite difficult to get at our place nowadays) FSB533-DDR266 FSB666-DDR333 (which step intel have skip) FSB800-DDR400. Some products have a FSB533 but have to use DDR333. I am getting all mixed up. Can somebody please help me to clear my mind up about all this mess?

Your help will be much appreciated!!!!

 

[cdogg]

The first step in understanding all the numbers is that the FSB is separate from the Memory Bus. Both don't have to match, though it's preferred.

For example, you can have the following:

FSB[tab]Mem Bus

266[tab]DDR266
266[tab]DDR333
.
.
.
533[tab]DDR266 or RDRAM PC1066
800[tab]DDR400 (because it's a dual config)


It might seem confusing, but as long as you can see they're independent from one another, you'll know enough. Typically, it's a good idea to have the memory and frontside buses to match. A DDR400 system with a 333MHz FSB will score less in benchmarks compared to a DDR333 CL2 system with the same FSB. This is because latency becomes a factor (the slowest component is bottlenecking the faster one). This is not always true in newer systems, but the general rule is a good one to follow.




~cdogg

"The secret to creativity is knowing how to hide your sources."
- A. Einstein

 

[pmonett]

What is messed up is that DDR400 is overhyped and underperforming. Most DDR400 mainboards perform better with DDR333 memory, especially with dual-channel chipsets.
Check out this link for a good example :

http://www6.tomshardware.com/motherboard/20030417/index.html

The summary is, in my view, that you should get a board that is compatible with DDR333 memory. Whether the board touts an FSB of 400 or not is irrelevant if it can use DDR333 RAM modules.
Then do not forget to add two RAM modules (especially if you go for an NForce chipset), and finally, a CPU that is also compatible with DDR333 memory. AMD ones are after the XP 2400+ (included), I think.

For Intel Pentium stuff, I think the waiting game is the one to play right now. Choosing a P4 for performance is a tricky business at the moment, until the 3.2Ghz gets out and chipsets are plentiful.
I know the quad bus is a real performer, I'm just not following Intel enough at the moment to give serious advice on which CPU and chipset to choose with it.

 

[cdogg]

I agree with pmonett. DDR400 memory is not the problem - it's the chipsets that support them. In every case I've seen, DDR333 outperforms its DDR400 successor.

However, Intel and others have begun to release Dual-DDR chipsets (Canterwood) which use DDR400 memory effectively. Unless your spending a lot of $$ on these puppies, it's best to stay away from DDR400 altogether...

http://www6.tomshardware.com/motherboard/20030414/index.html

~cdogg

"The secret to creativity is knowing how to hide your sources."
- A. Einstein

 

[dakota81]

What's even uber-confusing for a lot of people is the actual clock speeds versus the marketting termed clock speeds. DDR400 runs at a clock of 200MHz, but yet there's DDR200 which is marketted at 200MHz, but really runs with a clock of 100MHz. Althons are marketted with an FSB of 266MHz when it's really a 133MHz clock. Really confusing at times.

For optimal performance you would like to have the cpu fsb & memory speed match each other. In marketting terms, that would be like saying a 333MHz fsb athlon with DDR333 ram; 533MHz fsb P4 with DDR266 ram; or an 800MHz P4 with DDR400 ram.

With all that said, motherboards today will alow clock rates to vary between the cpu & memory, so don't worry about getting a combination that can't work.

 

[Psychosylph]

Just one quick note - DDR400 is not useless and overhyped. The key is to match your buses - if you are running: 166FSB, use DDR333 - 133FSB, use DDR266 - 200FSB, use DDR400. The reason that it is thought of as useless is when run asynchronously with a lower speed bus (such as Athlons are currently RATED ;-)) - it will actually degrade your performance. But this is true of any of the other memory types. So, if you are running FSB200, DDR400 will give you performance benefits...