Dresdenboys' blog: AMD Bulldozer - Patent based research part 2

[-Boris-]

Exactly, due to HyperTransport (FSB no longer is bottleneck) the memory does not really matter. The results are almost the same because of the higher the bandwith, the higher the latency. Overall performance in real world apps still the same no matter if you have DDR2-533 or DDR2-1200

Compared to GDDR, the DDR chips stagnate badly

Don't blame the memory chips, the problem is clearly an AMD only issue.
While Phenom II have seen very small advantages of DDR3, Intels LGA 1156 processors have much better bandwidth.

http://www.anandtech.com/show/2832/7

In many cases Athlon 64+ 6400+ shows better memory bandwidth than Phenoms, due to full speed IMC.
Overclocking the IMC cures the problem, but 3.5GHz+ IMC isn't really realistic.


A bit off topic, but just want to show how severe the IMC problem really is in the Phenoms.

http://www.madshrimps.be/?action=get...66&articID=909
66% higher IMC frequency gives 54% higher write performance. With DDR2 800MHz! DDR 400MHz wouldn't be far away in write performance!
Clearly bottlenecked by the IMC. At least read perfomance isn't crippled as much as write.

http://www.madshrimps.be/?action=get...65&articID=909
Overclocking memory gives much less perfomance increase in Nature test than overclocking the IMC.
However, read performance increases, hinting that it's the write operations that the IMC bottlenecks mostly, at least with DDR2 800, with faster memory the IMC should bottleneck read operations even more.

http://www.madshrimps.be/?action=get...67&articID=909
The Phenom II starts getting memory starved already after 1400MHz.


I would love to see these tests with a 3.6GHz Phenom II with at least 1600MHz memory.
And coupled with some real world game benches.