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Ram confusion - intel vs AMD

men8ifr

men8ifr

men8ifr

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26 Feb 2006
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83
I hope the (very) knowlegable people here could help me get my head around this...

AMD Phenoms can use DDR2 or DDR3 which depends on mobo? - is AM2+ DDR2 and AM3 DDR3.

I've read reports the AMD is just a bit slower than intel per Ghz but would that be with the intel on DDR2 and AMD on DDR3?

How much difference (e.g. gaming FPS and dvd encoding) would DDR3 make compared to DDR2.

The difference seems to be the cost of the Mobo's but the RAM is similarly priced?

Will the DDR3 system run into problems O/Cing more than a DDR2 system?

Is it likely some future AMD CPU's will only support DDR3 or will run markedly slower on DDR2?
 
AM2/+ CPU's can Run with DDR2 Memory.
AM3 CPU's can Run with DDR2 or DDR3 Memory

AM2/+ CPU's will work in a AM2/+ Socket
While AM3 CPU's will work in a AM2/+ and a AM3 socket
 
men8ifr said:
Does only the AM3 socket support DDR3, any ideas of performance differences?
Click to expand...
yes AM3 socket only support DDR3..

as for performance, my friend as a am3 system and he said he can't really see a performance boost much in real world performance, in benchmarks u will see more of performance boost
 
The only situation you should really be using DDR3 in is if you have to use it; for example if you're running a Core i7 system as they won't take DDR2.

There's no real speed advantage in the real world, and as long as you have a modern system you won't see any difference.
 
am3 processors can also work in am2+ motherboards just to through an extra bit of confusion there afaik

edit: woops see someone already beat me to that :)
 
Why is the AM3 with DDR3 not faster - the ram runs 33% raster (3 cycles instead of 2 ) right - surely that's got to make quite a difference?
 
men8ifr said:
Why is the AM3 with DDR3 not faster - the ram runs 33% raster (3 cycles instead of 2 ) right - surely that's got to make quite a difference?
Click to expand...

I suspect that the underlying memory arrays in DDR2 and DDR3 are much the same speed (if not identical). Isn't the main difference between DDR2 and DDR3 is the datarate on the interface. DDR3 can stream data back faster than DDR2 could ... however the delay from initial request to initial data ready is probably unchanged.

Thus, it may well be that DDR3 only wins over DDR2 when chunks of data are being streamed from the same RAM page .... modern CPUs do a lot to try to encourage this (memory controllers try to optimally order requests to memory, cache systems etc try to spot patterns in data request and speculatively request extra data they think may be needed later) but in a "normal" usage pattern then requests may be sufficiently random to nullify much of this benefit.
 
You might get up to a 10% increase with DDR 3 ovewr DDR2, for gaming its more about the CPU GPU combination, for AMD I suggest an ATI/AMD card with and AMD mobo. For Intel go for either ATI or NVidia.
 
Zeddy - does that mean there is something to be said for the AMD platform (spider etc) in that a AMD (ATI?) card will work faster in that system even though an equivelent nvidia card is as fast on paper (or on a referance system)
 
AM2+ and AM3 CPU's
This month (around the 20th Apr 09) AMD will release the Phenom X4 II 955.
Running at 3.2GHz the 955 will be the their fastest AMD desktop CPU, outpacing both the AM2+ Phenom X4 II 940 (3.0GHz) and the present fastest AM3 CPU; the 2.8GHz Phenom X4 II 925.
Until the recent release of the 925 the 940 was the clear leader in terms of CPU performance and requires an AM2+ motherboard. With the appearance of the 925 the optimal system became unclear, although the 925 was 200MHz slower than the 940 it could work on an AM3 Motherboard, with slightly improved architecture and slightly faster RAM (which also uses slightly less power).
The release of the 955 will mark a definite new emphasis towards AM3 architecture:
If you want the fastest AMD system you have to get an AM3 system and a 955.
However, if you just want the fastest AMD CPU, don’t worry - the AM3 CPU is backward compatible with AM2+ motherboards, giving people the option to upgrade their existing systems, without buying an entirely new system. So, if you want to upgrade the CPU on your AM2+ board you can buy the 955, knowing it will fit a new AM3 board should you decide to buy one down the line (when all the Bios and compatibility bugs are sorted)!
Although the clock speed difference is only about +7% over the 940, it would be an option for people with earlier phenoms, 9500, 9750...
It is also 400MHz faster (about 13%) than the 925, so for those that must have the fastest AMD system, 955 it is!
 
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There is no magical synergy that occurs when you put an AMD card into an AMD system.
Click to expand...

Not magical more logical as ATI is AMD it makes sense that the architecture is shared between the company therefore allowing for the optimisation of ATI cards on AMD chipsets, just like NForce and NVidia.
 
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