vmfs Benchmark changing over time

I'm in the middle of migrating esx4 to 5 and did some benchmarks again.

With SANHQ its nice to see whats going on on the san side.

All benchmarks shows as expected without the reallife benchmark with vmdk files.

I did the test on a new esx5 server with 2 san groups with one member each (ps3700 and ps4000) with MEM enabled and 4 gbit uplinks.

I had the same issue on another host with different hardware to the same san groups (also esx5 and MEM + 4 uplinks).

The first run on both was weird. At first it was slow with a queue depth of 1, but in the time it was going up. A second run just after the first showed better results.

I did not had this with iscsi volumes inside the guest vm.

1st run:

2nd run:

Anyone have a explanation?

Its no big deal, because the other benchmarks all showed fine...

some other screenshots:

100% read to 3700X 16x 400GB 10k SAS Raid 50 (with jumboframes):

100% read to 4000 16x 1TB 7200 SATA Raid 5 (without jumboframes):