Greetings all!

I'm trying to help my brother and my friend buy new computers, and as they don't have as much money to shell out as I did for my Dell 8400, I need some help in helping them throw together good systems for a low price. I should quickly point out they'll probably be using it mostly for games.

I've already checked out the Buyer's guide for Video Cards and CPUs, but there's no Buyer's guide for RAM, so, I apologize for any retreads of facts already dolled out on these forums (I did read through some of the posts, but I still have questions):

1. I've been hearing lately that the DDR2 RAM is actually slower in some cases than DDR. To what extent is this true? Are there any motherboards that can make better use of DDR2 RAM than DDR RAM? Is DDR RAM ultimately a better buy than DDR2?

2. What is the difference and significance of single-sided and double-sided RAM?

3. What's the difference and significance between dual-channel and regular RAM modes?

4. What's the difference and significance between ECC and non-ECC RAM?

5. Which RAM manufacturers are especially good and which ones should I avoid at all costs?

Any help here would be appreciated!


Mad Cat
>

DDR2 667 performs better than DDR400, even asynchronously. But beyond that, it's nothing special, at least not until companies start increasing bus speeds for their CPUs.

On top of that, it's not supported on AMD systems. And Athlon 64's are the best gaming systems out their. In fact, I own a P4 system, but won't be upgrading it because today's Intel processors are so poor: They perform worse than Athlon 64's while producing nearly 2x as much heat, drawing all that extra power, and requiring monster cooling that usually includes monster noise.

Best system for gaming with be a Socket 939 Athlon 64 system with an nForce4 chipset.

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they should get this memory kit of corsair 512x2 pc3200: VS1GBKIT400 paired with a s939 motherboard and athlon64

Thanks for the info so far. My brother might be getting an AMD system, but my friend is going with an Intel because he will be doing video and photo editing on his system, and I've read Intel's are better for that kind of stuff.


Mad Cat

There are two sides on any given stick of RAM. You can call each side a "bank" or a "rank" - the term will vary based on who you are talking to, but I use bank. Single-sided will only have memory chips on one side of the RAM - they only have one bank of memory chips. Double-sided sticks will have memory chips on both sides - they have two banks of memory chips. Almost all modern sticks of RAM that are 512MB or greater in size have two banks - you need to check the factory specs to verify. The significance of the single vs double sided issue comes from an dealing with Winchester core CPUs. Specifically, systems that have Winchester core CPUs will downclock the FSB to 333Mhz when there are more than 4 memory banks in your system. AMD corrected this issue with the new A64 Venice core CPUs.

Dual channel is not a function of RAM. It is a function of the chipset/CPU and allows faster performance (~5%) than RAM operated in single channel mode. In order to take advantage of dual-channel you must have a motherboard that supports dual channel and two sticks of the same size/compatible RAM sticks. Most RAM mfrs make matched pairs of RAM specifically to support dual channel. The kit that Danizaken referred to is one of those kits.

ECC RAM is typically used in server/workstation applications. You should be using non-ECC for making some gaming rigs. We can help you find the right stuff here...

Good RAM mfrs: OCZ, PDP System (Patriot), Mushkin, Kingston, Crucial and Corsair are all good RAM mfrs. Avoid generic ram like the plague.

Recommend you research a system and then post the specs in one of these forums - in your system make sure you post the following: BUDGET, PSU, mobo, RAM, case, CPU, vid card, DVD/CD and any other components you need to buy. Most modern mobos have integrated sound that is very good quality so you can avoid that cost. Don't skimp on the PSU and for best performance you will want 1GB of RAM (2 X 512MB modules).

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If gaming/cost are the primary considerations then I would highly recommend an AMD over Intel.

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So I take it your looking for a complete computer system for less than $600 ?

With a socket 939s mobo + AMD 64CPU, and a decent VGA card, plus I/O devices... you'll break $600 easy.

If you want good bang for the buck gaming PC you might want to check out a system with lower CPU frequency, better memory and high quality VGA card.

CPU---
I'd go with AMD XP CPU. You can find an XP 2800+ for around $90. It'll give you 2GHz frequency.

MOBO---
Socket A boards are cheap. ~$40 Biostar, or $50 Asus.

Memory---
Don't go cheap on memory. Buy from a reputable source: Kingston, Crucial, OCZ, etc... I'd suggest making sure you buy a memory module built using major brand chips: Samsung, Micron, Infineon. CL3, CL2.5, maybe CL2 depending on your budget.

DVD CDROM CD RW---
NEC 3500A model is close to $60

VGA CARD---
You could go with the more expensive 6800 series...
Or you could go with a GeForce4 Ti 4600 for about $125. It's still a kick arse card.

I'm sure you can find the rest of the stuff.

...just my thought.


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So, if I get a Winchester core CPU combined with 1GB (2x512MB) double-sided RAM, that's only 4 banks, will I have a problem, or is it only if I have MORE than 4 banks?

Yes, I know it's a function of the mobo, that's why I referred to it as a "memory mode". I'm still not sure what having dual-channel functionality will add to my system.

Thanks again!


Mad Cat


<P ID="edit"><FONT SIZE=-1><EM>Edited by madcat2099 on 04/26/05 06:07 PM.</EM></FONT></P>

More than 4 ranks - it should run like a charm with 2X512MB double-sided RAM.

I believe that dual channel effectively doubles the bandwidth of the RAM. Little help here Brent!

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More questions:

6. When buying RAM, is it better to buy Dual Channel matched RAM, or is it ok just to buy two the sticks independently from the same manufacturer?

7. What do CAS latency ratings mean and how much of an issue are they? And if it's not listed for the memory sticks, is there a standard CAS latency for unlabelled sticks?


Mad Cat

Technically, the sticks just need to be the same size/speed - they don't even have to be from the same mfr! That being said the best way to ensure that you achieve dual channel is to get a matched pair. Matched pairs have been tested by the mfr.

There is a recent thread in this forum that goes into CAS latency - do some reading and if you don't find what you're looking for then ask the question.

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Perhaps I'm asking the wrong question: I did read the bit about CAS latency, but I keep seeing people referring to their memory as preforming at "2-2-2-5 @ ###MHz". What are those numbers referring to?


Mad Cat

Saw someone post <A HREF="http://www.corsairmicro.com/memory_basics/153707/index.html" target="_new"> this </A>

Section 22 begins a discussion of latency.

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That was a Flinx post - cool tutorial!

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