Just an update.
In my OP I was actually WRONG ( yeah, I know, hard to believe right?
) Both numbers actually were right because there is more than one sensor. One program was monitoring one and the second program was monitoring the other (according to GPU-Z). Now my initial burn-in
stock test results:
Card: XFX 5770
Core: 850 MHz
Memory: 1200 MHz
Hash Rate: 180 Mhash/sec
1240 shares were produced with 21 stale shares for a stale rate of 1.69%.
Not too shabby for stock settings. Doing a test on core of 900 MHz and memory of 600 MHz next....
(update)
Core: 900 MHz
Memory: 600 MHz
Hash Rate: 188 Mhash/sec
1254 shares were produced with 9 stale shares for a stale rate of 0.72%.
Hash rate went up slightly, stale rate went down, temperature also went down by about 6C.
Next test is core 950 MHz and memory of 300 MHz.