I'm currently using Arctic Cooling Freezer Pro 7 on my E8400.When I oc to 4.05Ghz,my temps are mid to high fifties.I would like to have everyone's suggestions on a better "air cooler"...

http://www.frostytech.com/top5heatsinks.cfm

I'd go with the Xigmatek.

Define "best".

The Xigmatek HDT-S1283 is my first choice too. It's not the best as far as performance goes, it's not the quietest, but it's very close to best performance and best acoustics while still being relatively cheap. If money is no object and your first priority is performance then the champions AFAIK are these:

Noctua NH-U12P LGA775 AM2 Heatsink Heatpipe Cooler W/ NF-P12 120MM Fan -12.6-19.8DBA
http://www.ncixus.com/products/27130/NH-U12P/Noctua/ - best cooling, extremely low noise, $105

Thermalright Ultra-120 Extreme
http://www.ncixus.com/products/235 [...] RMALRIGHT/ - cools just as well, a little more noise, $58 + $20..$30 for a Scythe SFF21F fan or a Noctua NF-P12 fan

Thermalright IFX-14 Heatpipe CPU Heatsink Cooler LGA775/AM2 $76 + $20..$30 for a fan
http://www.ncixus.com/products/234 [...] RMALRIGHT/

I'm not worried about noise,or cost...I just want to get a few more degree's cooler on my cpu...thanks for the suggestions,I'm gonna look them over,and make a decision tonight and order one....

I don't think a better air cooler will make a meaningful difference. Read this article from anandtech , and look at the charts: http://www.anandtech.com/casecooli [...] i=3268&p=7

I've heard a lot about the ZeroTherm Nirvana beating every other cooler.
You might want to check that out too.

Hmm interesting read, makes me wonder if putting a similar push-pull setup on an AF64 Pro would yield positive results...

I'm using the Scythe Ninja in my HTPC cooling a C2D E6600 and a Tuniq Tower cooling a Q9450.

I did replace the Tuniq's fan with a Yate Loon though.

I just ordered the ZeroTherm Nirvana.It seemed like the best choice after I read up on it on other websites and reviews.As long as I can(hopefully)get 5-10 degree's cooler with it than my AC Freezer Pro 7,it will be money well spent...Once again I appreciate everyone's advice here...I enjoy reading Tom's everyday,along with everyone heres opinions.

Here's a nice chart for you.

Stock X6800 under load, cooled to 35 degrees by the Arctic Cooling Freezer 7 Pro and to 36 degrees by the Zerotherm Nirvana. Oops, the Freezer is actually better by one degree
http://www.anandtech.com/casecooli [...] i=3210&p=6

Overclocked X6800, at 3.83 GHz, idle: the Freezer gets it to 37 degrees, the Nirvana to 39. Again the Freezer wins.
http://www.anandtech.com/casecooli [...] i=3210&p=8

Overclocked X6800, at 3.83Ghz, under load: finally, the Nirvana wins, 53 degrees (the Freezer gets 58).

On the whole, I'd say you won't get 5-10 degrees better temps with your new cooler. Sorry... What you do get with the Nirvana is the ability to overclock higher, if you're going for the record and your CPU/RAM/mobo are all willing to cooperate.

Of course it would. More air flow= more static pressure=more heat removal.

Wrong. It's a good cooler, but it's poorly manufactured, and still not the best.

A better air cooler DOES make a meaningful difference. I would have liked to have seen this test on a CPU that isn't a few years old. That review just sucked hard.

At the end of the day, the TRUE is STILL the champion of the Air cooling arena.

The Noctua NH-U12P gets exactly the same temps or a little better and it's just as quiet, according to a review I've read recently. Keep an eye on it...
For example with an X6800 overclocked to 3.94 Ghz the Noctua gets 55 degrees and the TRUE 59.

http://www.ncix.com/products/index [...] ure=Noctua C$60
http://www.ncixus.com/products/ind [...] ure=Noctua US$106

No idea why the prices are so horribly different in Canada and the US, BTW.

http://www.anandtech.com/casecooli [...] spx?i=3268

Well, according to this review the IFX-14 is probably the best, although not for those kinda prices, over her in the UK, its onl £35, while the TRUE is nearer £40,
http://www.madshrimps.be/printart.php?articID=680

Just me........

I guess I should change what I actually need.My mobo limit is 1800 fsb...@4.05Ghz,my AC Freezer Pro 7,my cpu temps are high forties at idle.Under load it goes uo to high fifties,low sixties...hopefully the Zerotherm will keep it cooler under load???

I heard great things from the Zerotherm Nirvana, and it is quite cheap when on sale. This cooler should match or beat an unlapped TRUE.

My guess is that you'll see at most a ~5C improvement over the AC7.