M18xR2 7970M /HD4000 running on 330W vs 240W vs battery

[jywang]

330W 7970M enabled: 3DMark11 score: 10312 (11160, 9031, 7600)
240W 7970M enabled: 3DMark11 score: 2466 (2371, 3534, 2144)
On battery 7970M enabled: 3DMark11 score: 2645 (2380, 8568, 2137)

330W 7970M disabled: 3DMark11 score: 820 (696, 7334, 825)
240W 7970M disabled: 3DMark11 score: 825 (701, 7339, 824)
On battery 7970M disabled: 3DMark11 score: 823 (700, 6838, 826)

So, it seems that when running the Intel HD 4000, the performance doesn't differ between battery or power supply used.

When running on 7970M, it is almost better to be on battery rather than use the 240W adapter.

[TheMatrixHacker]

I don't think your supposed to be running those cards in Crossfire on only a 240W adapter. I just went through a nightmare trying to figure that out because a tech at dell said you could but after consulting people here on the forums they said no. after escalating my question at dell I was told by a senior technician that in no way were you supposed to run SLI or Corssfire with a 240Watt Adapter.

[jywang]

When you connect the 240W, it says that it will run with reduced performance. Since 90% of the time I'm not running games and I have extra 240W power brick for the my office, I thought it was good to know that I get decent performance on the CPU as long as I have the 7970M switched off.

BTW running on battery with my config and 7970M enabled, it looks like it is draining approx 23W/hr with the screen brightness turned to minimum and 28W/hr turned to max brightness. This equates to between 3 and 4 hours of operation on battery.

When I disabled 7970M, it is draining only 16W/hr on low brightness and 20W/hr which means I should be able to get between 4.5 and just over 5 hours on battery. Nice.

[Arcticsoldier]

thanks for that, thats good info. with the Asus G71/74 i could only get 1hr running on powersave profile. looks like the battery on the alienware running powersave is much better