All I can say is, having 5 fans so close together, would pretty much reduce the airflow. What I see is you have 2 fans on the HS trying to force air through it, with a 3rd exhaust fan, then 2 fans pulling up. Might want to experiment what would work best for ya on that.
With ambient temps of 22C, I can only assume that you temps could be better.
I have ambient room temp of 30C, and my Q6600 (OC 3.2ghz) is testing Prime95:
C0 - 57C
C1 - 57C
C2 - 56C
C3 - 56C
As far as Memtest, perhaps your copy is messed up? Did you get the latest?
i think your temps are about right. the place where you and i live ranges greatly in temperature. in the summer (now) the temperature of the area is 98-105F (36-39C) not to mention i live upstairs so it gets hotter than downstairs. my temps go down a lot at night due to the ambient temp...you're good.
as for the fans, i know its kinda a mess pulling in all different directions
however the top 2 ones are really silent, and in normal conditions my CPU push&pull + rear exhaust are only running at 600-700rpm, which, partly relies on the top 2 to get the heat out.
when its 100% though, I have adjusted it so it is just right at full speed at 1600rpm, and gives the same temp results as above under load
Ahhh.. okay, that makes sense.
I think my setup is quiet. Although my CM 590 is housing my dual core. My Q6600 is in an AeroCool Engine PC which is actually doing pretty well to my surprise.
Forgot to explain how I have my 590 setup. I have a side fan 140mm and one 120mm on the top. The are both on a fan controller switch (5v/off/12v). I turn them on or off when needed, also I use the top as an intake not an exhaust. I think its better to be able to push cool air (5v) from the top in front of the Tuniq when it does get too warm. Also I have the side to push air out. I think neg pressure does work well when your trying to force hot air out, which the 2 top fans your using is basically doing the same thing, but doesn't work in favor of your HS, as far as keeping airflow in a direction.
The Tuniq 120mm fan, 2 front 120mm bay fans, and rear exhaust fans are also on the controller but knob adjusted.
But it looks like a good clean setup. Hope you can find out the memtest problem.
A search in google I bumped into my own thread again.
Just an update:
As someone sugguested to me, the memtest 86+ error was a USB legacy setting problem in BIOS. In the ASUS P5Q deluxe motherboard BIOS setting, set USB legacy from AUTO to Disable will get ride of the memtest errors.
Also a new bug I have discovered, if you ever get 112 deg C reading from your CPU temp all of a sudden, it is one of the new ASUS bios update bug. I believe it is the 1201 version. Once you update it to 1301 it get rides of the problem. It is not a bug in ASUS AI suite - its the BIOS. I have seen people with different CPU having the same problem also, be it E8400 or Q9450.
I have tried overclocking it, stable at 3.5Ghz with 1.3V. Temps are around 70 deg C for all 4 cores from speedfan. I decided its abit too high so I'm running it on stock clock again. I have not come up with an application that requires full power from my CPU anyway, so its not much point for me.