Graphics card registering without PCIe cable.

I've just got a second gtx 670 and while I was installing it I realized I didn't have the PCIe cables for it, while they're being sent up I've just left the new one plugged into the motherboard without being plugged into the PSU. I opened GPU-z today to check some temps and both cards seem to be registering. One made by EVGA and one by MSI as it should be, both cards are also giving sensor outputs. Does this mean the new card is as normal? It does say that SLI is disabled and I haven't installed the drivers for the new card either. I'm just posting here to see if anyone knows whats going on or is it just GPU-z giving false sensor readings. Also the MSI card is displaying a clock of 915MHz not 965MHz as it should be, is this just it scaling down to the clock of the slower card or is it GPUz sensing there's a card there but getting confused with the readings?

Sorry to bombard you with questions.

This sounds like pretty standard behaviour for this kind of situation. Your new card is normal, if you tried to use it for SLI or anything else 3D without the power cable, it will spit out an error message. As for clocks; I can't say what GPUz is doing right now, but once you're all plugged and in SLI, yes both cards will run at the clock speed of the slower card, but you can bump the clock speed, just like you would with a single card, using your software of choice. Having both running at 965, should be no issue for 670's.

Cheers just wanted to make sure I wasn't gonna fry it.

The PCIe slot provides a significant amount of power, and some graphics cards can run on nothing but the slot power, but they're (for obvious reasons) not that powerful.

The reason you need PCIe power cables is because your average cards need much more electricity to run at full pelt than the slot alone can provide.