Corsair HydroCool 200

Very good external watercooling kit – Joe

SUMMARY: A top performing kit at a reasonable price.


The good guys at Corsair Memory were nice enough to send a sample of their latest product, the Corsair HydroCool 200 to test out. This is a diversification by Corsair, noted for their memory products.

Of more significance is the fact that this product was developed by Delphi¹. This is a well established company that booked $27.4 Billion in automobile related sales last year. According to Corsair, Delphi Thermal Systems designed this unit. I believe Delphi Thermal Systems is part of the Safety, Thermal and Electrical Architecture division, which booked $9.7 Billion in sales during 2002.

Folks, there’s a clear message here: PC Watercooling is attracting the big guns.

I would not be surprised to see additonal “big guns” entering this market, either directly or through marketing alliances with some familiar names. The second message is even more clear:

Watercooling is going mainstream.

My opinions, but sure looks like watercooling, once dominated by techies, is seeping down to the non-techie – big time. One of the great things about the Overclocking crowd is that we get a good view of what’s coming down the pike, usually by one to two years.

The HydroCool’s key features include:

  • User programmable temps for alarm and shutdown
  • Low fluid alarm
  • Visual flowmeter
  • Copper waterblock with thermal probe
  • Temp controlled fan speed (50% @ 35C, 100% @ 45C)
  • Fan override switch
  • Fail safe shutdown

The instruction manual is nicely done, comprehensive and easy to read. The retail price in the US is supposed to be about $215 – very competitive with other systems.

First I’m going to give you a detailed look at what’s inside, and then a performance test using the Die Simulator.

Shipping with the HydroCool 200 are the following parts:

All Parts
  • Copper waterblock (nickel plated) with thermal probe and 3/8″ tubing
  • Fluid additive (to control algae and corrosion)
  • Clamps for Socket A and P4
  • Interface card for system control (not a PCI card)
  • Interface cable
  • Quick connect connectors and clamps

¹ Delphi is part of the more widely known company of AC Delco, which is spinoff from General Motors – Thanks Steven and Tom!

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Initial Impressions

When I opened the shipping box, the HydroCool was wrapped in clinging plastic – I quickly found out it was clinging because it was wet. Somewhere in the HydroCool there was a leak. The system was not totally dry (probably tested before shipping) and I was concerned that the circuit board might short out if not thoroughly dry.

Normally I would test it first, then take it apart to look at the innards; this time, I took the cover off first to mop up water and make sure it was dry before firing it up. Removing the cover required that I remove some plastic fan studs holding the fan grills in place – once done, the cover came off easily after removing four screws. I’ll discuss what’s inside after taking a look at the key components.

The waterblock is not large:

WB Top

it measures 50mm/2″ square. This gave me some pause – waterblocks of this size usually are not strong performers. The base


shows some polishing marks but I could not feel them, so they are minor.

The front panel


shows the LEDs and four control buttons – one to set, two for temp (C or F), and one for over-riding the fan to run it at full speed. The back shows


the two quick disconnect hose connections and the control cable port. This is used to power the external box and relay temp data for fan control.

What’s Inside

With the cover removed, I found the leak:


This is the cap which holds the low-water alarm in the reservoir. Even fully tightened, it still leaked slightly. The moral here is not to overfill the unit and don’t tip it. I can’t tell you this is a generic problem, but it’s something to watch.

With the cover off, you can see the fan


a 120mm x 37mm unit – pretty hefty. On the right is the PCB control panel and in front of the fan is the 12 volt water pump – there are no external power connections needed, it’s all powered by the PC’s power supply. The pump is nicely done – it’s mounted in a large rubber collar to isolate noise from the case.

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Looking down into the case


shows the reservoir on the left, the fan/radiator (5½” x 7″) at top, the pump in the lower middle, the flowmeter and front panel PCB at the extreme right. The flowmeter lights up when powered:


Left – Off; Right – powered.

A side view shows the rad


and the quick connect fittings at the rear. A look from the other side


shows the pump – note that the fittings between the reservoir and pump are larger than the tubing size (1 3/8″ vs 3/8″ OD) – something I have not seen before. To the right of the center strut you can see the large rubber bushing which holds the pump in place – a nice move for sound isolation.

The control card


has connections for power, the waterblock’s temp probe and the motherboard’s power switch. You remove the power switch pin from the motherboard and plug it into the power switch cable supplied with the HydroCool. The purpose is twofold:

  • Turns the HydrCool on when the PC powers up
  • Shuts down the PC when waterblock temps exceed a set limit

I really like this last feature – if for whatever reason water stops flowing and temps escalate, the controller shuts down the PC. Note that this is independent of the Operating System – it’s a hardware shutdown. Users can program the shutdown temp.

The controller fits in a PCI slot cover, but does not mount into a PCI connector – it’s free standing. What’s nice about that is if all your PCI slots are taken, you could remove the slot cover and mount it inside the PC, allowing room in the case for the tubing and interface cable.



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Performance Test

On powering the HydroCool, it beeps once, the fan runs first at full speed, then quickly slows down. I measured fan speed at 1471 rpm @ 26.0C waterblock temp and 2252 rpm @ 24.5C at the Turbo setting. At the low setting, I could not get a reading for system noise 3′ away with a Radio Shack sound meter – < 50 dBA. However, the noise you hear is not so much from the fan but the pump - sounds like a low humming noise.

At the Turbo setting, fan noise is louder – I measured it at 57 dBA three feet from the fan – not terrible, but definitely noticeable.

I tested the HydroCool kit using the Die Simulator with the Socket A clip. The clip is stiff, engages three socket lugs and you need a screwdriver to mount it on the socket lugs.

Test Results


Die Temp

Ambient Temp



HydroCool, 74.8 watts, 2252 rpm

37.6 C

20.9 C



HydroCool, 74.7 watts, 1471 rpm

39.4 C

21.6 C



Delta = CPU temp – Ambient Temp
C/W = Delta / CPU Watts

Interpreting C/W: For every watt (CPUw) that the CPU
consumes, the HSF will limit the CPU’s temperature rise to (C/W x CPUw)
plus the temperature at the HSF’s fan inlet. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that CPU temp will increase 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

At its highest speed (Turbo), Die Simulator results place the HydroCool at the top of watercooling kits tested to date (Heatsink Ranking). At its low fan speed, results still place the HydroCool in the top rank. This is much better than I expected, considering the smallish waterblock.


Corsair’s collaboration with Delphi has produced a very good external watercooling solution. With retail pricing expected around $215, the HydroCool 200 looks like a very competitive kit for aggressive cooling with easy setup effort.

For a first time effort, Corsair/Delphi hit a homerun – not unexpected considering the resources that this team can bring to the party.

Thanks again to Corsair Memory for sending this our way.

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