Hi tuxxdk welcome to Sevenforums.
Personally, I would go with Bitlocker, I use it myself and there is little to no slowdown, I mean if its there, we are talking milliseconds.
As for not having a TPM motherboard, don't worry about that. We have a tutorial made by our very own Brink which will show you how to turn that particular check off, all you will need is a USB flash drive (In fact, you don't even need that, I use an SD card as my key): BitLocker Drive Encryption - Windows 7 Drive - Turn On or Off with no TPM
Hope this helps