Is it ok to have 8GB and 2GB sticks of RAM?

I currently have 4GB of RAM (2x2 GB). I was originally going to upgrade by getting two 4 GB sticks and replacing the two 2 GB sticks I have for a total of 8GB. But then I noticed that I could get one 8GB stick for the same price as two 4's, and combine it with one of the 2GB sticks already in my machine, giving me 10GB total. That way, I would end up with extra RAM and only waste 2GB of RAM. However, I was wondering if doing this would have any (negative or positive) performance impact or causing any problems with the motherboard. 

So --> Upgrade to 2X4, or 8 + 2?

Additionally - How can I tell if I have DRR3 -1066 or 1333? Short of opening the chassis and looking inside?

Side note:

I will also be upgrading my onboard graphics to an AMD Radeon HD 5670 with 2GB of memory, if that is at all related.

ALSO: The RAM will all be the same type.

Motherboard Info from HP:

http://goo.gl/wRpDe

Memory Info from HP:

Memory

!\[\](http://h10025.www1.hp.com/ewfrf-JAVA/Image/common/Collapse_Individual_default.png) 4 GB

• Amount: 4 GB
• Speed: PC3-10600 MB/sec (message as PC3-8500)

!\[\](http://h10025.www1.hp.com/ewfrf-JAVA/Image/common/Collapse_Individual_default.png) Memory upgrade information

• Dual channel memory architecture
• Two DDR3 DIMM (240-pin) sockets
• Supported DIMM types:
• PC3-8500 (DDR3-1066)
• PC3-10600 (DDR3-1333)
• Non-ECC memory only, unbuffered
• Supports 2GB DDR2 DIMMs
• Supports up to 4 GB* on 32 bit PCs

Thanks in advance.