Article Type: Hardware
Article Date: October 24, 2001
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Cooling: More Than a Heatsink
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| A Performance Case |
When I first overclocked a Celeron 300 about four years ago, I thought I had finally arrived at the gates to gamers' paradise. Here I was with a CPU that cost me only about $150 US, and I was able to run it at 450 MHz!
Naturally, I checked into the best cooling available. At the time it was a dual fan setup on a single big heatsink. My Celeron ran warm, but I never had any heat problems or crashing and it was working perfectly when I upgraded to a faster Celeron a year or so later.
These days we are into 1 GHz CPU’s, and we’re still clocking them as much as 50 percent over rated speed. Both heat and power issues are becoming more and more serious. In fact, it’s no longer enough to worry only about the best fan and heatsink combo, now we are having to also worry about general issues of airflow inside our boxes.
This means asking questions about case fans, both for intake and exhaust. It also means checking out better power supplies and cases with extra outlets and inlets for additional fans. In short, it’s becoming quite a complex affair to keep our system units cool.
This article will address some of these issues for the novice, as well as make a head-to-head comparison between some of the more recent additions to the CPU cooling race. We’ll also briefly visit the Peltier connection, since there was a time when it was well worth while to consider the Peltier as an effective improvement to CPU cooling.
The Race is Not to the Swift
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| Water Block Cooler |
Recently there have been a spate of articles on the Internet reviewing the latest CPU heatsink/fan combinations. These items of hardware are generically referred to as HSFs.
The best of the HSFs currently are OCZ’s Gladiator, and the Alpha PAL 8045. We’ll look at both these units, as well as a couple of different fan combinations that produce efficient cooling without the decibel output of jet engines.
The important issues for HSFs are three: efficient heat transfer, efficient airflow to get rid of the heat, and a reasonable noise level. These elements cover the micro level of the unit and CPU combination. The fourth element gets us into the macro issue of the case environment. It isn’t much good to blow a ton of air through a very efficient heat sink if the air is already hot. Aye, and there’s the rub!
Your HSF will drop in efficiency as the temperature in your case rises. It’s for this reason that there are a lot of specialized cases out there, and though they fetch a premium price (up to $120 US) they are well worth the investment where maximum cooling is required.
The HSF Outlook
About a year back when I stepped into my first AMD Thunderbird rig I purchased a unit made by ATTech that was made completely of copper. This was probably one of the first all copper HSFs on the market.
When my ATTech CM25 arrived I was already using a Golden Orb HSF on my Athlon, running a Thunderbird 800 CPU at 945MHz.
The CM25 improved the cooling of my AMD Tbird by about 3 degrees Celsius under load. It did this primarily by improving the heat transfer, and not by increased airflow. Copper is simply an excellent heat conductor, and much better than aluminum. I used the VIA utility to measure the CPU temperature, and the operating environment was unchanged between the two HSFs.
The OCZ Gladiator
Recently I read about The Overclockerz Store at The Overclockers Wet Dream and so I began to check out their products. Then I saw a review of the OCZ Gladiator somewhere, probably at Athlonoc. It sounded like this unit was worth checking out.
When the OCZ Gladiator arrived on my test bench I was intrigued, to say the least. The heatsink itself is completely copper, just like the ATTech. The heatsink itself is about 30 percent larger than the ATTech, but the primary difference is in construction.
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| ATTech CM25 |
I removed the ATTech from my machine to compare the units side by side.
The first noticeable difference is weight. The Gladiator weighs nearly double the weight of the ATTech unit.
The ATTech has about 22 fins; the Gladiator has 38. The fins on the Gladiator are extremely thin. The greater number of fins provide more area for airflow, and as a result the heatsink itself gets rid of heat more effectively than the ATTech. How much more effectively, you ask?
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| OCZ Gladiator |
Under moderate load on a 1 GHz Thunderbird clocked to 1.4 GHz, I achieved a temperature of 39.5 C with the ATTech CM25. This was in a case with ample cooling, by the way. We’ll talk more about that later.
Under the same conditions the OCZ Gladiator with the 60mm Delta 7K fan achieved 35.2 C. That is a HUGE difference in performance!
Of course, that performance comes at a price. The Delta fan achieves 68 CFM of airflow, and it sounds like a small hurricane. Many users aren’t prepared to put up with that much noise to achieve high efficiency. Thankfully, there are options. But before we look at them, let’s look at another recent entry into the CPU cooling competition.
The ALPHA PAL 8045
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| ALPHA PAL 8045 |
The ALPHA PAL 8045 (AP8 hereafter) is NOT a completely copper heatsink. Instead, this unit has copper imbedded in the heatsink so that the contact point to the CPU is copper.
In spite of that difference, the unit proved even more efficient than the OCZ Gladiator, but there are some niggling issues that will make the Gladiator the better choice for some system builders.
First of all, this unit is huge. It comes stock with an 80mm fan, and the unit is the same size. Consider for a moment that this is almost double the area of a 60mm HSF. For that reason, and because of the weight, you can’t simply open up your system and clip this unit onto your CPU. Instead, you have to remove your motherboard and use a special mounting system developed by ALPHA.
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| 8045 on the mainboard. |
The AP8 comes complete with screws, washers, nuts and springs to mount the unit. Once you’ve done the installation you can remove the unit later without having to remove the mainboard again.
The fact that you must remove your motherboard isn’t a deterrent to those building a new system. It’s really a very simple process, and installing the ALPHA took me about ten minutes once I had removed my mainboard. But for others who may never have installed a mainboard, I suggest you stick with the OCZ Gladiator.
While this isn’t a HOW TO about installing HSFs, please don’t forget to apply a thin layer of thermal grease when you install your HSF. More on this later.
When I first tested the AP8 I tested with a 53 CFM Mechatronics fan. The Mechatronics is a great deal quieter than the more powerful Delta 68 CFM fan, yet the temperature under load with the Mechatronics was almost the same as with the OCZ Gladiator running the more powerful Delta, only .6 C higher.
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Comparison Chart  |
After swapping the Mechatronics for the higher output Delta fan, the temperature came down to 34.3 under load, a full 1.5 C cooler than the Gladiator. Where decibel level is a concern the lower output fan is very effective. Where maximum cooling power is needed this unit is hard to beat.
