I recently bought a new 320Gb hard drive for my computer to set up RAID 1 on it for some added security. Installation went as smooth as could possibly be (plug in power, plug in data cable, start up computer, Intel software recognized new drive, right click create RAID 1, done!).

However, for some inexplicable reason, I seem to have strange test results when using BENCH32. On my old configuration, a single 7200 rpm drive, I achieved about 60 MB/s write and 70 MB/s read. With a new RAID 1 configuration, I would expect the write to be slightly diminished but read to be significantly improved (though not exactly double speed). However, with the new configuration, I am getting 90 MB/s write and only about 80 MB/s read.

I should NOT be getting improved write performance, especially NOT better than read!

What's going on?

My system setup is:

q6600 2.4ghz CPU
4Gb DDR2 667mhz RAM
on board Intel ICH9R "RAID chip"
2x Seagate 7200 RPM 320GB drives in RAID 1
Widows 7 home premium 64-bit