450W with a sandy bridge pentium and that graphics SHOULD be ok, unless that ps is super cheap and it isn't putting out nearly the power as it should be. Shouldn't have anything do to with ur tv either, my tower is hooked up the same way. If your computer is stable running with a BCLK that high and the temps are ok then go for it, but overclocking via BLCK (which is your only option for OCing with that CPU) runs EVERYTHING is your computer faster, including your graphics card, so that is probably causing your lines. Most systems wont tolerate increasing the BCLK more than a few ticks above stock. My i3-2120 won't go higher than 104 vs 100 stock with good internals. i also have a 450W ps but its 80+ certified.
Also get more RAM asap son!