How large is your windows swapfile?
Is the swapfile located on the first partition (C:)?
Does your backup use a usb interface? usb 2.0? usb 3.0?
My 8GB system usually doesn't use the swapfile.
When I'm running many applications, my swapfile usage is below 180MB. YMMV.
Heavy swapfile usage slows down your system.
The attached screen-shot shows my hard drive performance.
The first boot partition is on the left of the graph and the remaining partitions are located to the right of the graph.
You hdd performance decreases when the partition is located further from the first partition.
At the time of the benchmark, none of the hard drive partitions were on 4K-aligned boundaries.
Check out new SSD: OCZ Agility2 60GB (Extended Capacity), post #44 to see how 4k-aligned partition alignment improves hard drive performance by 10 - 20%.
For optimal performance, ssd partitions must also be 4K-aligned.
When you use win7's Disk Management to create partitions, they will automatically be 4K-aligned.