A question regarding DDR2 Ram

[psyborg]

I'm hoping this is not an inane question...I did try to browse around and didn't see these two questions addressed directly. So if they are dumb please be gentle


1) Is DDR2 ram considerably less forgiving than DDR was? I have been looking at possible upgrades and have noticed ALOT of problems posted by people for incompatibilities between various boards and memory. And not just the cheaper modules here either. I'm wondering if this is just me seeing the complaints because i'm looking closer...I don't remember seeing a large number of compatibility complaints in DDR memory.

2) In regards to DDR2 memory. If I was going to an E6400 processor, what is the reason for choosing DDR2 @ 800 mhz as opposed to 533 mhz? Strictly speaking it seems that 533 should cover the needs of the processor. Is overclocking the only reason to go with the 800mhz modules or is there something important I'm missing here. My first instinct was to go with the 800 mhz modules, but as I do not frequently take the time to OC my processors I wonder if I'm wasting cash.

Thanks for any help you can provide. I'm a long time lurker, but this is my first time to actually post

 

[SEALBoy]

1. The basic incompatibilities with DDR2 RAM and mobos is voltage. If I remember correctly, OCZ RAM in particular runs at a different voltage than other RAMs. Most mobos should have a compatibility list tucked away in the manual (my ECS mobo does), so you can choose from there.

2. Depends on what you do. If you're not going to be gaming, 533 is fine. Heck, I'm using 533 and it runs fine even in games. But if you're building a heavyweight computer with a nice graphics card, you should probably stick with 800 RAM to avoid bottlenecks, especially since there isn't a big price difference.

 

[fredgiblet]

1. Some RAM makers made non-standard sticks that caused problems, the DDR2 spec is no less forgiving than DDR, it's just the implementation was screwed by a couple makers

2. If you aren't planning on overclocking you should grab some 667, why 667? Because then if you get a new proclater that uses a 1333 FSB you can run the RAM at a 2:1 ratio. Unless you are insanely overclocking or running an AMD X2 you don't really NEED 800 RAM

 

[Mondoman]

...
1) Is DDR2 ram considerably less forgiving than DDR was?

Fred pretty much nailed this. The DDR2 market is still evolving and not mature. High-end DDR2 modules command high prices and produce high profits, but the technology is not quite there to get good yields that will run at the standard 1.8V. Thus, most manufacturers advertise their high-end modules by their "manufacturer-sanctioned overclock" specs, not their standards-compliant specs. OTOH, all DDR2 modules must be bootable/usable under standard conditions (although perhaps at slower speeds/timings). Some manufacturers (such as OCZ) seem to emphasize performance over compatibility, and so their modules don't work on some boards. As long as the modules are covered by warranty, though, the manufacturer should replace them with modules that work at no charge, or refund your money.
See also this post: http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1249881#1249881

2) In regards to DDR2 memory. If I was going to an E6400 processor, what is the reason for choosing DDR2 @ 800 mhz as opposed to 533 mhz? Strictly speaking it seems that 533 should cover the needs of the processor.

Yes, as long as you are running in dual-channel mode.

Is overclocking the only reason to go with the 800mhz modules or is there something important I'm missing here.

Mostly yes, or as Frank mentioned, in case of a possible future upgrade to a CPU with faster FSB. 1333MHz FSB will require DDR2-667 RAM speed to match.
You can run the memory faster asynchronously from the FSB and get small performance improvements; if you are only running one "step" faster (e.g. DDR2-667 for 1066MHz FSB), some benchmarks may actually end up slower unless you are using very low latency RAM. By two "steps" faster, even longer-latency RAM should show at least a bit of an increase. This article has some tests along these lines: http://www.madshrimps.be/?action=getarticle&number=1&artpage=1962&articID=472

I think the bottom line today is that the C2Ds are so easy to OC that I would plan on running one between 333 and 400MHz FSB, meaning that the RAM would be running faster than DDR2-667.

 

[psyborg]

Thanks all. Nothing here shocking, but I wanted to be sure I wasn't making any faulty assumptions.