As I'm typing this it's 12AM and nearly 90F at my place. With every fan on blast my CPU is idling at 44C - if I remove the OC it's still at 38C. I'm considering LC but to me the cost can only be justified if I saw sub-30C temps in this kind of heat... with the OC Is it possible? How much should I expect to invest?
My current setup:
i7 920 @ 3.8GHz with Hyper 212+ (Antec 900 case)
1. Ambient temperature
As the temperature inside your room (ie ambient temp for your system) is 90F (32C), a stock i7 920 idles at 38C is not unreasonable at all, with Hyper 212+.
And if this 90F comes at 12am, then I can imagine it will be hotter at 1pm or 5pm.
2. You might want to look at both ventilation inside and outside the case.
One critical element is your graphics card. The photo is too dark and I do not see it well. Which model? If it dumps heat inside your case, it is almost certain that those hot air will be sucked by the push fan of your 212+ and will go though the heatsink before expelling out (either via case top or via case rear). Obviously, this is no good.
Note: Click User CP at the top and then Edit System to the left to fill in details of your system
If your case sits in a tight spot (eg underneath a desk or even worse, inside a cabinet) with bad ventilation around it, all the hot air expelled from the case can get accumulated very quickly in the region and will 'significantly' negatively impact the thermal performance of your system.
These few points must be addressed. If they are not 'solved', going the route of watercooling does not help much. That is, hot air dumped inside case will still go through the radiator, resulting in not-so-pretty temp. Hot air will still accumulate outside and will make the watercooling system not optimally effective.
And last but not least, welcome to OCN as I see this is your first post!