Quote Originally Posted by Hans de Vries View Post
Doesn't show Istanbul's real potential.

1) Not using the bandwidth
2) Not using the cores
3) Not using the power budget

800 MHz DDR2 is simply not enough for many throughput applications.This is
currently a (temporary) Server platform limitation. Frequency scaling is just
38% (out of 100%) for SpecFP_rate. Just look at the six core Dunnington
to see what a lack of bandwidth does:

4 Socket: SpecFP_Rate: 4 core Nehalem 3.33 GHz: Xeon - X5570: 372
4 Socket: SpecFP_Rate: 6 core Istanbul 2.8GHz: Opteron 2439SE: 283
4 Socket: SpecFP_Rate: 6 core Dunnington 2.67GHz: Xeon X7460: 156

4 Socket: SpecInt_Rate: 4 core Nehalem 3.33 GHz: Xeon - X5570: 499
4 Socket: SpecInt_Rate: 6 core Istanbul 2.8GHz: Opteron 2439SE: 416
4 Socket: SpecInt_Rate: 6 core Dunnington 2.67GHz: Xeon X7460: 294

SPEC_2006

Dunnington has a 20% higher Floating Point peak performance as
Nehalem (63.85 vs 53.28 GFlops). Dunnington has 9 times the L2
cache amount as Nehalem (9MB vs 1MB) and Dunnington has twice
the amount of L3 cache (16MB vs 8MB).

But Nehalem runs circles around Dunnington in Spec_FP_rate because
Nehalem has a 3.75 times higher bandwidth as Dunnington (32.0 MB/s
vs 8.53 MB/s)

Istanbul with DDR2 is simply not that much better off with 12.8 MB/s.
(DDR3 should be better with 21.3 MB/s)



Regards, Hans
Since when was the X5570 3.33GHz?