As stated earlier for me:
Intel Core i3 4350 3.6 Ghz CPU, 8 GB memory, 64 Bit Win 8.1, Intel HD4600 GPU
The other is AMD 3.0 Ghz 6 core CPU, 8 GB memory, 64 Bit Win 8.1, ATI 4670 GPU
I record in .ts format, however, I did some tests this morning with .jtv, and it didn't appear to make a difference...1 recording was 25-29%.
I wonder if Win 8.1 is to blame...
I have a prime at work, so I will install MC on my machine here (Intel based with NVidia GPU), and see how it performs.