CPU'sIntel Pentium 120My first computer used a pentium 120 processor. It had passive cooling. Boy, those were the days. I still have the processor... Intel Pentium ProMy second computer had dual pentium pro's. The pentium pro was a big leap beyond the pentium. It did really fast 32 bit operations. It had lots of fast cache. It was really expensive. The motherboard was the Intel Providence motherboard, which is how a server motherboard should be designed. The actual processors were rated at 166mhz, and had a 512mbyte cache. I bought them used, and they were overclocked to 200mhz. I was a bit worried at first, but I never had any problems with the cpu's being overclocked. I suspect that Intel had great yields of their Pentium Pro's and decided to mark some to run at 166 mhz, since they couldn't sell them all at the more expensive 200 mhz cost. This taught me that it is often a good idea not to buy the fastest rated processor, but rather get a cheaper one in the hope that it will overclock. This has proved to be a good idea, see Intel Xeon for more details. The p6-166 with 512kb of cache uses 27.5 - 35 watts according to intel. The p6-200 with 512kb of cache uses 32.6 - 37.9 watts according to intel. |
I bought 2 Celerons (433 MHz) for an ABIT-BP6 system that I put together. They worked fine. I bought another ABIT-BP6 system, and 2 more Celerons (466 MHz). These have less cache than the corresponding Pentium II processors, and were much cheaper in their day. They also run quite cool, relatively speaking.
The Pentium III was a major step up from the Pentium II, mainly in clock rate. It comes in two basic flavors, slot-1 and socket 370. Slot-1 is much bulkier. I have an IBM system with with a slot-1 PIII which has a large heatsink and a shroud leading to the power supply exhaust. No actual fan on the processor. A good, reasonably low power processor.
My third computer had dual pentium III 933 'Coppermine' processors. It has 256k of L2 cache. The P3 was much faster than the pentium pro 200. It uses about 29 watts, which is pretty similar to the pentium pro 200. One limitation was the Asus CUR-DLS motherboard motherboard has the processors so closely spaced that I could only use 60mm fans on the cpu coolers, which made them a bit noisy.
Of the socket 370 Pentium III's, most have a bare die visible on top of the package. This is known as package FC-PGA. The newer ones have a heat spreader. This is known as FC-PGA2. Coppermine processors (the 933's and 1000's) can be found with both types of packaging. Needless to say, the FC-PGA2's are far less fragile when installing the heatsink.
I bought an AMD 2000+. It uses more power than my Pentium III processor. It is the first processor that I bought that acutally consumes more power under load than under idle. Under idle conditions, it stays significantly cooler. It has a bare die visible on the top of the package. It also comes with 4 spacers which are placed near the corners of the package so that the heatsink can't easily break the die. AMD later learned their lesson, and used a heatspreader on top of the die to reduce breakage. My AMD 2000+ is still running fine.
My dual pentium III 933mhz machine was showing its age, so I decided to get a new computer. I was looking around, and found some some low voltage Xeon 1.6ghz cpus available. The Xeon 1.6 Prestonia is based on the pentium IV, and designed to support dual processing. I am not a big fan of the pentium IV or the Xeon due to it generating lots of heat (58w at 2.0ghz, 65w at 2.4ghz, 74w at 2.8ghz, and 103w at 3.2ghz), but the low voltage Xeon runs at only 1.3V (the bios reports 1.28v) and is rated at 30 watts (at 1.6ghz) , which isn't much higher than the 28 watts of the pentium Pro 200 or the 29 watts of the Pentium III 933. I was able to overclock the LV Xeon to 2.4ghz by increasing the front side bus from 100mhz to 150mhz without changing the cpu voltage. This was done by changing some jumpers on the motherboard and a BIOS setting. The Xeons have worked fine at the higher clock rate, and likely dissipate 40 watts (at 2.4ghz) each at the higher clock frequency. Like my Pentium Pro's, I think the 50% overclock was possible because Intel was making lots of fast processors, and likely labelled these as 1.6ghz even if they could run much faster. And they only cost $119 for two, which was a great deal!
Using the BIOS of the Asus NCCH-DL or the Asus PC-DL I can set the multiplier for the cpu from 12 to 16, where 16 is the default. For my PC-DL I ran the multiplier at 16 and the front side bus at 150mhz. This yielded pretty fast main memory access as well as fast cpu performance. For my NCCH-DL I have set the multiplier to 14 and the front side bus to 133mhz in order to increase main memory speed without making the processor run very hot. It is likely that I could increase the front side bus further if needed. It is possible to run at higher than 2.4ghz by increasing the cpu voltage. This has the possibility of shortening the CPU's life, as well as generating more heat. I have resisted doing this, in the interests of running cool.
Please see Intel Windtunnel HSF below for details about that heatsink/fan for the Xeon. Please see CoolermMster 3U Xeon Heatpipe HS below for details about that heatsink for the Xeon.
My original LV Xeons had reached their maximum overclock (at standard voltage) of 2.4ghz, so I bought a pair of 2.6ghz LV Xeons on ebay for $32. They are quite similar to the SL6GV Xeon LV 1.6ghz processors, being Prestonia, 130nm process, and the same voltage of 1.3v. I believe they came from Google, who ordered these special LV Xeons from Intel. It is unclear what the thermal design power is, but I estimate it is roughly 43w. The part number SL7HU doesn't show in any official Intel documentation. They are Prestonia, Family F, model 2, Stepping 9, revision D1, x26 and 100mhz. They work fine in my motherboard, and I have overclocked them to 2.86ghz where they are running fine. There are many faster processors around, but these are fast enough for now :-) I have been able to overclock them to 3.12ghz by increasing the front side bus from 100mhz to 120mhz without changing the cpu voltage. I know at 133mhz (3.46ghz) they won't work at the default cpu voltage.
Using the BIOS of the Asus PC-DL I can set the multiplier for the cpu from 14 to 26, where 26 is the default. For my PC-DL I am running the multiplier at 26 and the front side bus at 110mhz. This yielded pretty fast main memory access as well as fast cpu performance. So I have improved my overall clock speed from 2.4ghz with the 1.6ghz lv xeons to 2.86ghz with the 2.6ghz lv xeons. Not too bad for $32.
The SL8GU is based on 90nm technology, unlike the SL7HU and SL6GV. It has twice the L2 cache, 1mb compared to the slower Xeon LV's. It is based on the Nocona core, unlike the slower Xeon LV's which are based on the Prestonia core. It runs at a lower voltage of 1.1125-1.2v, unlike the slower Xeon LV's. It it unclear what the thermal design power is, but I estimate it is roughly 55w. It features the EM64T (64 bit) instructions. I may buy a pair if I can get them at a low price for my fileserver, as I heard that solaris likes 64 bit processors for ZFS computations.
I got a new processor with my new ECS motherboard. I picked the E-4500 processor. It runs pretty cool, and comes with a pretty good Intel cooler. If I had a more expensive motherboard, I am sure I could overclock it, but my cheap ECS motherboard doesn't like to be overclocked at all. The processor automatically changes its cpu multiplier and voltage as a function of cpu load. At lower multipliers it runs at lower voltage, and as the multiplier goes up, so does the voltage. If you are running Windows, you can download RMClock, which is a program that can adjust the voltage at each multiplier. There are similar programs for Linux. Using RMClock, I was able to set the voltage of the maximum multipler to be the same as the minimum multiplier. I was unable to decrease the voltage at the minimum multiplier, which may be a limitation of the voltage regulator or perhaps the ECS motherboard. As a result, the processor uses significantly less power when loaded, and hence less heat and noise is generated. This is a lot more advanced a processor compared to my low voltage Xeon processors. The wonders of technology...
I bought a notebook with this processor. I have been able to undervolt it using RMClock, and it runs quite cool. I couldn't lower the idle voltage much, but I was able to lower the high load voltage significantly.
I bought a notebook with this processor. I have been able to significantly undervolt it using RMClock, and it runs quite cool. At idle, the power consumption is down 50% from the factory default!
I bought a notebook with this processor. I have been able to significantly undervolt it using RMClock, and it runs quite cool. Performance isn't nearly as good as I would expect based on the reviews I have read.
In the old days, you put a heatsink on top of your processor, made sure some air flowed over it, and you were done. Those days are generally long gone.
When I got my first Pentium IV based Xeon system, I looked around for a decent heatsink. The Intel Windtunnel was reasonably priced, and the reviews said it performed pretty well. I bought a pair. They can have the fan mounted two ways, either blowing air from one end of the heatsink to the other, or blowing air down on the heatsink. The first method is clearly superior and designed for 2U rack mount servers. It does require lots of free space on the motherboard for the fans to fit on the side however.
I used the Intel Windtunnels to cool the LV Xeon. My motherboard wasn't even close to having enough space to mount the fans on the side. Therefore, I mounted the fan on top of the heatsink and to blow air down. This isn't nearly as efficient an airflow pattern, but it does cool the voltage regulator on my motherboard. It works ok. It has a pretty loud 60mm fan (I think it was 6000rpm normally, and 4000 under light load when the motherboard slowed it down). Newer versions of the windtunnel come with 38mm thick fans, while mine were 'only' 25mm thick. I eventually replaced the fan with a 60-80mm fan adapter and a 3000rpm 80mm fan. It worked as well as the 60mm fan, and was much quieter.
I had heard that the coolermaster 3U heatpipe coolers were the best available for the LV Xeon. I eventually bought a pair and installed them. You have to remove the motherboard from the case to access the rear of the motherboard to change the backplate. It was a bit of work. I secured the same 80mm fans to the heatpipes via copper wire, as I didn't have monster fans inside my case as rack mount server cases usually do. I also added a really small 40mm fan to cool the voltage regulator on the mb. This has reduced the cpu temperature by a few degrees C. It isn't a big difference, and isn't worth the price increase over the Intel Windtunnels, unless you want a quieter computer.
When I got my Asus ncch-dl motherboard, it was designed for the Nocona Xeon. The Nocona is a higher clock rate processor that consumes more power. So Intel needed a bigger cooler. They specified 4 holes in the motherboard that are roughly 3/8 of an inch in diameter. The heatsink doesn't attach to these holes. Rather the heatsink attaches through these holes, to the motherboard tray. For those motherboard trays that don't have mounting studs in the right place, there is a plate with adhesive that Asus (and others) sell, that comes with an alignment guide to put the plates (dual processor) in the correct place on the motherboard tray.
Anyway, the Intel 2U passive cooler is a massive piece of copper, weighing about 3 lbs. There are many thin fins soldered to a plate which is roughly 1/4 inch thick. This plate has 4 captive bolts that go through it, and attach to the motherboard tray studs. I operated my xeons without fans for a few minutes, and I found that the upper one was getting a bit warm for my tastes. I don't have a 3U case, nor do I have screaming fans to blow massive quantities of air over the heatsinks. Fortunately, I had two 80mm slow, quiet fans and some thin, solid copper wire. I removed the heatsinks, and ran the wire around the heatsink, inside of the captive bolts. I then ran the wire through two holes in the fan. I did the same for the other side. After twisting the wire a few times, the fans were securely mounted to the heatsinks. Now the processors run nice and cool, and are much quieter than they would be in a typical 3U case.
For the pentium socket 5 and 7 and the pentium III and AMD K7 chips, life was tough. The typical heat sink had a springy clip to hold it down to the motherboard. One end hooked onto the socket, and the other usually required great pressure to attach. Intel and others finally wised up, near the end of the Pentium III era. I have some Intel PIII heatsinks that have a 'hinge' at one end, with a place for a finger to aim as well as compress the clip to hook onto the CPU socket. Previous to that, screwdrivers were often employed, and if they slipped (as happened far too often) would crash into the motherboard, often with bad results. I eventually learned to use a needlenose pliers or micro-needlenose pliers instead of screwedriver in order to be sure nothing would slip and crash into the motherboard.
As processors drew more power, the cpu's got hotter, the heatsinks got bigger, and a more secure method for securing the heatsink became necessary. There are a variety of solutions. The pentium IV based xeons have 4 holes through the motherboard (though the size of the holes vary depending on the if the xeons are prestonia, nocona or something newer). For the prestonia Xeon, there are clips on plastic guides that either clip down on either end of the guide as well as the middle of the guide, or for some aftermarket guides there are clips that fold down 90 degrees to secure the heatsink. For the nocona Xeon the holes mate with threaded studs that are attached to the motherboard tray. Then four screws are tightened down between the cpu and the motherboard tray, bypassing the motherboard. This is needed as some prestonia heatsinks like the Intel 2U passive cooler weigh 3 lbs. The Core-2-Duo HSF has 4 pushpins to secure it to the motherboard.
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