Advanced Micro Devices Inc (AMD)

[sgolds]

Elmer, those SPEC scores - why is Itanium so mediocre?

Company Name; System Name; #CPU; Base; Peak
CINT2000:
Dell; Precision Workstation 360 (3.2 GHz P4, DDR400); 1; 1205; 1249
SGI; SGI Altix 3000 (1500MHz, Itanium 2); 1; 1077; 1077

CFP2000 Rates:
Dell; Precision Workstation 360 (3.2 GHz P4, DDR400); 1; 1267; 1285
SGI; SGI Altix 3000 (1500MHz, Itanium 2); 1; 2041; 2055

http://www.spec.org/osg/cpu2000/results/res2003q3/

OK, Itanium is putting up good floating point numbers, but they are getting spanked in integer! This is not what was predicted by posters here.

Let's see, how does this compare with older Itaniums?

CINT2000:
SGI; SGI Altix 3000 (1000MHz, Itanium 2); 1; 683; 683
CFP2000:
SGI; SGI Altix 3000 (1000MHz, Itanium 2); 1; 1396; 1410

http://www.spec.org/osg/cpu2000/results/res2003q2/

OK, that gives us a 50% increase in clock rate, (1077 - 683)/683 * 100 = 58% increase in integer (very good) and (2041 - 1396)/1396 * 100 = 46% increase in floating point (still pretty good). Conclusion: Itanium is scaling pretty linearly with clock speed, so far.

It is worth comparing hardware specs:

Hardware Vendor: SGI
Model Name: SGI Altix 3000 (1000MHz, Itanium 2)
CPU: Intel Itanium 2
CPU MHz: 1000
FPU: Integrated
CPU(s) enabled: 1
CPU(s) orderable: 4-64
Parallel: No
Primary Cache: 16KBI + 16KBD (on chip) per CPU
Secondary Cache: 256KB (on chip) per CPU
L3 Cache: 3.0MB (on chip) per CPU
Other Cache: N/A
Memory: 2 GB
Disk Subsystem: 1 x 36 GB SCSI (Seagate Cheetah 15k rpm)
Other Hardware: None

Hardware Vendor: SGI
Model Name: SGI Altix 3000 (1500MHz, Itanium 2)
CPU: Intel Itanium 2
CPU MHz: 1500
FPU: Integrated
CPU(s) enabled: 1
CPU(s) orderable: 4-64
Parallel: No
Primary Cache: 16KBI + 16KBD (on chip) per CPU
Secondary Cache: 256KB (on chip) per CPU
L3 Cache: 6.0MB (on chip) per CPU
Other Cache: N/A
Memory: 4 GB
Disk Subsystem: 1 x 36 GB SCSI (Seagate Cheetah 15k rpm)
Other Hardware: None

(Amazing that they don't specify FSB or DRAM speed!)

So, to get the nice scaling scores, DRAM was doubled, I'm not sure about DRAM speed, but everything else is pretty similar.

Conclusions:

MHz scaling is impressive, but this still looks like a highly specialized processor focussed on number crunching applications. Integer performance is pretty pathetic, it is beaten by P4 (and if we find the numbers, obviously beaten by Athlon and Opteron also).

This is not the all-around fastest processor on earth, but it does make a good claim to be the fastest floating point processor. The trend is clear: Itanium seems destined to be a good processor for scientific calculations. A quick review of the SGI 4, 8, 16 & 32-way configurations shows good scaling here, also: FP 82, 164, 327, 644; INT 98, 195, 185 (no 4-way here).

If you can afford the cost then this makes a good supercomputer backend for number crunching. This does not look like a processor for the general computing market.

Postscript: Sun results continue to be awful. They should really pack it in!