I also have a dual-core Haswell CPU (Pentium G3258) except that mine has the multiplier unlocked, lacks SMT, and has a weaker iGPU. That combined with my CRT monitor (which can run at any resolution up to 2048x1152) mean I can nearly re-create your performance situation by underclocking my CPU and making a custom resolution of 1366x768, thereby allowing an independent look into your SVP performance and see what's going on.
However, your software setup seems a bit questionable considering your TV and your PC hardware. In particular, why not just change your TV's refresh rate to be an exact multiple of the video framerate and change your TV's resolution to match the video resolution (so that the TV does the upscaling)?
I know that the refresh rate change can be done automatically via MPC-HC since I use it myself, and I believe the resolution change can be done automatically by MadVR thought I am unsure of this. This way, except maybe for widescreen content lower than 720p, you could not worry about upscaling with MadVR which would take some load off of your PC to allow more headroom for SVP. Regarding refresh rates, many TVs have a 59Hz (59.94) available by default in Windows without the need for custom resolutions and/or refresh rates, so if 59Hz is available for selection then you might as well use that and not worry about ReClock.
EDIT: Before you do any of that, try the following "quick fix"...
1. Reset your profiles to 2g
2. Set SVP's "Interface type" to "Advanced"
3. Select SVP video profile 1920x1080@24
4. In the new window that appeared, change the value for "Motion vectors precision" from 'One pixel' to "Two pixel", then click OK
5. Now select SVP video profile 1920x800@24
6. Once again, change the value for "Motion vectors precision" from 'One pixel' to "Two pixel", and click OK
7. Test with a 1920x1080 30fps video; if you need one, try this video I normally use (not great quality, but it works): http://mediafire.com/download/ua8i0kdcvd1wqo5
8. Now try a 1280x720 30fps video, which should test SVP+MadVR upscaling; if you need a sample for this as well, I also have one (same footage as above but at 720p and better quality): http://mediafire.com/download/s525ycmc05nbohs
If you can handle both of those videos just fine, then you shouldn't need to worry about anything else.
(the only exceptions would be formats that you can't decode in hardware, like VP9, h.265/HEVC, or 10bit h.264/AVC, or the rare video that's strangely intensive for SVP to handle)