unclewebb and I have been trying to determine when +2 turbo (25 on i950 or 22 on i920) is active. Turning off all cores but 1 in bios is one way of seeing +2.

Another way to get +2 turbo is enabling c3/c6 in bios with all cores active. (C1e/eist can be enabled or disabled). And at least on my bios/mobo, you have to run at stock mhz for this to work.

By running spi, can prove the multi is indeed 25 when all 4 cores are active in bios just asleep via c3/c6 except active one, here are pics with unclewebbs V8 turbo.

pic 1, all cores active in bios with c3/c6 enabled, the loaded core goes near 25, and in proportion to the load.


Using task manager to force spi to stay on thread 0,1 ie core 1, it tends to stay around 24.5 to 24.6...but dont know if v8 program running is inhibiting other cores from fully sleeping, cpuz will bounce back between 24 and 25. I tried running v8 on thread 0 and spi thread 1, but never saw full 25, but still get up to 24.6.


Here is with 1 core active in bios, still c3/c6 enabled....locks on 25.


spi proof of 25 multi at stock with all 4 cores active in bios and c3/c6 enabled
25x133 (1 core active in bios) spi with c3/c6 enabled for apples to apples comparison. 4 runs spi 1m
12.449
12.449
12.480
12.449


Next up 24x133, ie, turbo running spi with all cores active in bios, c3/c6 disabled, so turbo is limited to 24.
12.808
12.824
12.807
12.823
12.808


Next up, 24x133, ie turbo running but with c3/c6 ENABLED, to allow 25 multi to show up...and spi proves it is indeed same speed as proven 25 multi with 1 core active in bios.
12.449
12.386
12.433
12.434


So definitely getting 25 multi with all cores active in bios as long as stock mhz and c3/c6 active.

One other point, enabling c1e, eist, or c3/c6 does slow down spi slightly which is why you have to run 1 active core in bios with c3/c6 enabled for fair comparison.