All the reviews I've seen have shown the PEP66 beating the PAL6035 by a couple of degrees, not the other way round. Go with the PEP. Hell is right though (sounds weird huh?), 900 is more realistic - 1gig is quite possible, but enough cpus don't make it that far to stop it being anywhere near certain.
The PEP-66 is superior. However, running it on an S370 or Socket A mainboard adds complication to answering sleddog's original question. The PEP-66 was designed to hang on a Slocket. Running this HS on a S462 or S370 mobo can be done. Many mainboards can not accommodate the PEP-66 in its original configuration--the HS requires a lot of real estate. There is a 10mm thick ~20 cfm, 60mm fan made by Delta that makes shoehorning the PEP-66 onto many S370/S462 mainboards possible. As a 20 cfm 60mm fan is a BAD joke, a PAL-6035 is a better cooling solution in this case, hands down.
However, the PEP-66 is easily modified. The original configuration can be changed to a "normal" Socket A setup. Then the HS/CPU junction is on the bottom of the HSF, rather than on the side. When this is done, the PAL-6035 can NOT equal the cooling ability of the PEP-66. Using a 42.5 cfm 80mm case fan on top of the PAL-6035(easier said than done!) will not beat the cooling ability of the PEP-66 with a 60mm 33 cfm fan on top of it.
Why I asked the original question is that I have a PEP on my Celeron and a PAL on this Duron (see sig). I'm contemplating switching them.
By the way, do you know that a Delta black label fan running at 7v outperforms a Sunon 23cfm running 12v? Tested it myself... on the PAL... difference of about 2C both idle and max. At this voltage the Delta is quite livable. I've got the Delta wired to a 7v/12v toggle switch. I run it 7v normally, but switching to 12v has two advantages: (1) cpu is cooler; (2) wife is happier 'cause she thinks I'm vacuuming