Thermochill radiators are expensive because they are made in the UK. But the PA series mean serious cooling business.
However, in the lower mid to low cfm/airpressure catergory, i think the Swiftech quiet power radiators are very close performers to the PA120's. But aside from that, the PA series rule the mid to high cfm/airpressure category and also perform very well at low cfm's. I reckon the CoolingWorks CoolRad 22T and 32T are good mid cfm/airpressure performers as well judging from their specs (forget about the 12T however, its another BIX clone).

The old Black Ice rads (not the GT) aren't actually the best performers around. One that has particularly gained a not-so-good reputation these days is the Black Ice Xtreme. Its so airflow restrictive that according to some user tests, at 100cfm, the BIX and BIP perform the same. The black ice pro will be a better choice over a BIX unless you are gonna run super high cfm fans and go insane from the noise. Well, noisy WC setups don't float my boat.

The problem with the old Black Ice Pro and Black Ice Xtreme is that, its using a dated design, and not so good manufacturing process (check out the internals of its flat tubes). Its high fin density and restrictive design makes less efficient at using the available airflow. If it were yesterday, the Black Ice series were some of the best PC specific radiators you could get. Today's generation of radiators with the Thermochill PA series, CoolingWorks CoolRad 22T and 32T, and the Swiftech Quiet Power series employ lower fin density, making it much more efficient with low to medium cfm fannage, and also proves itself to be better even at high cfm fannage. However, for those on a budget, the Black Ice Pro still holds its worth.

The Black Ice GT's however, seems to take an even more contradictary methodology from the latest trend of PC radiators, employing even higher fin densities and said to use thinner fins. HWLabs were running into a financial crisis and needed to come up with a long overdue refresh in its product line, and here comes the GT's. We do hope they come up with something truly worthy with the GT's. We'll see how they do in testing.

EDIT: perhaps try checking out these threads:
http://www.xtremesystems.org/forums/showthread.php?t=99721
http://www.xtremesystems.org/forums/showthread.php?t=102243

This post has been edited by MetalZone: Jun 8 2006, 11:52 PM

LOL of course I don't mean that. Thermochill's are for those who can afford it.
The new black ice GT's should perform better than the black ice Pro though.

how sufficient would depend on your standard of how close to ambient temperatures you want them to be.
you'll need at least a 2X120mm radiator. so a BI GT stealth 240 or swiftech MCR220-QP is the bare minimum.
from ur sig, u're planning to WC your LP nf4 (non expert) chipset? thats gonna be a problem coz not many blocks can support it (alphacool's nf4 block can), but blocks of this nature are overly restrictive and seriously hamper your flow rates.
The only block I would recommend if you wanna cool ur chipset in the same loop as ur CPU is the swiftech MCW30. no channels and pins of any sort to reduce flow restriction, but not compatible with the regular LP nf4's; on the expert can.
otherwise, avoid cooling the chipset block in the same loop, use a better heatsink instead (rlhh was bulking one that can fit the LP nf4).
well, the above is much more relevant if you're going for a high flow, high restriction CPU block (like the Storm G4). You'll want to avoid anything that is overly restrictive to your loop as it will cause your CPU temps to suffer.

question, did you choose the apogee because swiftech's website claims it's better than the storm?
or is it cost wise?
on the other hand, i dare say i think a swiftech MCR220QP will perform better than a BI GT stealth 240. dont take that by word until proper test results come out tho.

This post has been edited by MetalZone: Jun 12 2006, 06:32 PM

alright then, fair enough if the improvements are not worth the cost for you.
about keeping the loop low restriction, not necessarily true. the only things that should add significant restriction to your loop are those whose temps matter the most and worth the flow rate drop in exchange for better temps (provided you chose an appropriate block). and in this case, the CPU, followed by the GPU.
your D5's high head would be worth putting on a good high restriction CPU block. makes more sense to put the flow into good use.
the nature of high restriction blocks is that they perform better with high flowrates (and to acheive that you need a high head pump), provided the added restriction actually makes sense to do something.

The BI Micro is a joke. avoid it unless you have absolutely no choice but to use an 80mm radiator. same thickness and high airflow restriction as the black ice xtreme.