Confusing performance numbers

drakioned · 8 Mar 2012 at 15:19

Hi,

I have two computers that do not very much other than run SETI@Home and World Community Grid.

One is a HP Microserver N36L with an Athlon II Neo (dual core / 1.3ghz) and 4gb RAM, the other is running a Core 2 Duo E6420 (dual core / 2.13 ghz) and 8gb RAM.

The performance numbers aren't very far apart in terms of what SETI@Home is reporting.

The Athlon II Neo 1.3ghz numbers are:
Measured floating point speed : 1160.47 million ops/sec
Measured integer speed : 6028.9 million ops/sec

The Core 2 Duo's numbers are:
Measured floating point speed: 1757.18 million ops/sec
Measured integer speed : 6354.36 million ops/sec

Are these numbers right? I would have thought that a 4mb cache Core 2 Duo at 2.13ghz would totally destroy a 2mb Athlon II Neo at 1.3ghz... whereas it seems like a 50% difference in floating point and 5% difference in integer.

Indy500 · 8 Mar 2012 at 17:28

Congratulations on discovering that clock speed isn't everything.

You'll find that in independent benchmarks C2D's integer performance isn't much better than Pentium Ms (they share a common base design), Intel focused on improving the FP capabilities.

drakioned · 9 Mar 2012 at 11:40

Well, but given that the Neo should be some low power bottom of the range CPU, I would have expected a bigger difference.

Indy500 · 9 Mar 2012 at 15:24

drakioned said:
Well, but given that the Neo should be some low power bottom of the range CPU, I would have expected a bigger difference.

The difference is there in the floating point numbers. Since both CPUs (Athlon II and Core 2 Duo) are in the same ballpark when at the same clock speed, that difference is entirely down to the latter.

drakioned · 9 Mar 2012 at 19:48

Well, I had BOINC rebenchmark the numbers, and the new numbers are:

Core 2 Duo @ 2.13ghz:
Measured floating point speed: 1759.04 million ops/sec (from 1757.18)
Measured integer speed : 6720.51 million ops/sec (from 6354.36)

Athlon II Neo @ 1.3ghz:
Measured floating point speed : 1165.41 million ops/sec (from 1160.47)
Measured integer speed : 6052.98 million ops/sec (from 6028.9)

I don't know how much I trust these numbers if just re-running the benchmark gets me another 350 millions ops/sec...

drakioned · 10 Mar 2012 at 14:30

I reinstalled Ubuntu, and ran the numbers again for the Core 2 Duo:

Measured floating point speed: 2010.21 million ops/sec
Measured integer speed: 11509.06 million ops/sec

These seem more along what I was expecting now.