I am running 5850s and a 6970 (the latter of which was always slower using phatk kernel as opposed to poclbm kernel until 1.50).  The latest Phoenix 1.50 seems to be significantly better.  I applied the #define fix, which I think is a bug fix more than an enhancement [judging by the stale percentages over the short term ... so the jury is still out I guess] and I am getting between 1.5-2.5% additional on my 5850s (nothing too aggressive, XFX boards of standard specs, factory voltages and 850-875MHz core and 700mH memory clocks between them) and about 2.5% on my 6970 (MSI, also standard spec board at factory voltages with the core clock at 920MHz and the memory clock at 1375MHz).  Note that I use the machine with the 6970 in it for day to day business and all day work via VPN/remote desktop (32-bit color full screen locally ... XP on the other end, so only one monitor) and I leave Aero on.  Win7 x64 on all machines except one which is Vista x64.  Aero off on all except my workstation with the 6970.

THERE IS A "MINOR" BUG IN 1.50 HOWEVER.  I don't know if the #define fix tickled it or if it was there before and I didn't notice it [I have only been using 1.50 for a few days anyway].  Soon after starting the miner on my 6970, long polling push came through and it shows 1 rejected in the phoenix console,  however, Deepbit did not show any rejects on it's side (0.00%).  With several previous versions, the accepted/rejected values ALWAYS matched, even after days, however, there were other issues as many have experienced.  I am curious, is the reject being shown because phoenix is now finding the occasional hardware error and counting it as a reject [without submitting anything] as opposed to simply burying it in previous versions?  Another reject came along after that, also following a long polling push and the console shows 2 rejects and deepbit shows 0.76% stale (131 accepted and 1 stale is 1/132 = 0.76%).  So, clearly one was a standard reject [stale/invalid] from the pool and the other from Phoenix itself.  I just verified on the others, and one of them also has one extra reject (in fact, that is the only reject it has). Phoenix is showing more rejects than Deepbit ... for the first time in many versions.

The reason I wonder if this might be because of hardware errors is I was playing around with Diablo Miner yesterday.  Achieved great hash rates as reported by Diablo; about the same as I would get with Phoenix 1.50 or slightly better [not as good as Phoenix 1.50 with the #define fix using phatk].  Diablo showed very very few hardware errors (according to the forums, it was low .. less than 3 in 1000 for any card, and in some one case only 1 in ~2000).  However, Diablo currently has a TERRIBLE problem with rejected shares (4%-8% per miner instance for me ... -v 2 -w 128 on all instances and I think -f 10 on the 5850s and -f 30 [default I believe] on my 6970 since it is the machine I use for other things and often.  I was so horrified that I ditched Diablo without even a report on their thread.

Having said that about the odd "extra" reject noticed in two miner instances, I have not seen another one since on any of my miners, but they have not been running all that long either (about 35 minutes).  In fact, in this time, there are only 3 rejects among all my miner instances and two of them are reported by Phoenix and not by Deepbit.  Accepted share count exactly matches on each miner to what is shown on Deepbit, so it isn't a big deal; but I would like to know what is causing the extra rejects reported locally only.