AMD CPU limitations

toma_alimosh

Also known as "Myke Hunt"
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Ok, so I'm in the market for a new computer and doing a bit of research on parts and costs. Unfortunately I haven't kept up with PC technology lately and learning new things. I get most anything about new changes, but this one seriously puzzles me:

I went on a canadian computer store's website to look for parts and prices, and when I looked at some of AMD socket (AM2+ socket) motherboards, under specifications as to what memory it will take, they write this:

*Due to AMD CPU limitation, DDR2 1066 is supported by AM2+ CPU for one DIMM per channel only. Refer to www.asus.com for the memory QVL (Qualified Vendors Lists).
I don't get it, what does that mean? What is this limitation that new AMD CPUs have? If anyone can explain this to me and what that would mean about my future purchase, please do ... I'm completely out of the loop on this one.
 
i think it means if you run 2 sticks in say slots 1 n 3 or 2 n 4 it'll work at that speed..... ie normal dual channel mode with 2 DIMM's which is what most people do.

however, if you were to fill all 4 DIMM's with ram, you'd be reduced to running at a slower speed, probably DDR2 800 or something like that.

im pretty sure this limitation has been around for some time, even on the skt 939 boards your ram speeds were limited when you filled all 4 DIMM slots, but to be honest in most cases having more RAM way out weighed the fact that you couldnt run them at full speed.

simple solution is to just buy a 4 gig kit.... ie 2x2GB DIMM's and be done with it.

to be honest with you, why arent u going intel? i am a big fan of AMD but really they have lost their way and their advantage. Intel have long since put the netburst behind them and surpassed AMD in most cases. AMD just arent where they were a few years ago when intel were fumbling around with the rubbish pentium 4 chips. AMD's built in memory controller is still novel though.


but yeah, im pretty sure thats what it means..... fill all 4 DIMMS and your speed is reduced, im sure this trait has been around since the birth of AMD's Athlon 64 processors. AMD's built in memory controller is a great idea and provides the CPU with a direct link to the memory, but there must be some inherent design problem with addressing memory that way that means it just cant cope with full speed access to that many DIMM slots. it'd probably increase the cost of the chip a fair bit to rectify or something.
 
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to be honest with you, why arent u going intel? i am a big fan of AMD but really they have lost their way and their advantage. Intel have long since put the netburst behind them and surpassed AMD in most cases. AMD just arent where they were a few years ago when intel were fumbling around with the rubbish pentium 4 chips. AMD's built in memory controller is still novel though.

Actually haven't decided yet between AMD and Intel. I'm researching both and I found the comment a bit odd. Thanks for clarifying.

If that may be it ... then I may pick Intel after all. I need as much speed as possible for accessing memory and HDD.
 
In plain English, it means if you use 2 sticks of DDR2 1066 RAM it will run in dual channel mode, but if you use 4 sticks of 1066 it only supports single channel.
 
I thought the Phenom CPUs doesn't use single or dual channel mode anymore, they call it "ganged" or "unganged", and it can be set to either one in the bios.
 
Memory limitations are due to whatever memory controller you're using. With AMD, it's in the CPU, and with Intel it's in the Northbridge chipset on the motherboard. I'm sure Intel systems have their own limitations (I don't think any of their desktop boards can handle 32 GB of RAM, for example, while some AMD ones can), they just don't have anything to do with the CPU. There's not much point in running DDR-1066 on an Intel system anyway, since they still use a FSB, which can be saturated with dual-channel DDR-667.

Regardless, however, Intel has the performance crown right now, so you should go with them, unless you're building a super-budget system and won't be doing any overclocking.
 
Overclocking is overrated anyways.

(I underclock my cpu's for fun and profit; or rather, they do it themselves)
 
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