Zalman CNPS6000CU <BR> <BR>Overall really good product. <BR>Completely silent with the rheostat turned up. <BR>Looks great. <BR>Definitely worth the money – I paid £38 + p&p. <BR>Easy installation. <BR>XP 1600+ temps: 49C idle, 52C loaded. <BR>Not much quieter than a retail HSF with the rheostat turned down though. <BR> <BR>Now just to replace that PSU... <BR>
[addsig]

Totally agree. Perf-wise its not an overclocker, it just keeps you cool for less noise. I must say however that the installation was not quite as easy as I read. Of course maybe I just have no coordination. Those fins just bend a little too easy, and they never go back quite right.

Still, about the best $40(US) I ever spent.

Out of the box no mods they are probably the best amd cpu cooler thats also quiet, however with a small amount of effort I prefre the likes of AX7, PAL8045, MCX462, and SLK-800 with a undervolted panaflo 80mm for their even lower noise and slightly better cooling, and better clip. Zalman uses single lug unfortunately so the full CU version is quite heavy considering that mounting method, at least the thermalright coolers use triple lug clips, which is better although I still prefer directly mounting to the mobo for anything near 500g.

-Ken

Have you personally compared noise levels between Zalman and any of these? I have the Zalman, it's fairly quiet to me but I can always use something even quieter.

yeah I agree with Gxcad about the two lug mounting system that's probably the only thing that has stopped me from getting a Zalman yet be careful if you move round your case to like LAN's and stuff otherwise your CPU may be *permantely* silenced

I think the Zalman's retention clip is sufficient at least for an Al-Cu version but of course the case should be moved around carefully. Of course I'll take no responsibility of my evaluation

mine works as well in silent mode. but i'm getting slk-800 because what i really want is ultimately the passive cooling with case airflow alone created by three 80mm panaflo L fans. i tried zalman passively and my advise to you is don't do it, or have a second cpu lying around and get ready to piss your pants when motherboard utility warning and mbm5 warning kicks in both together with loads of beeping.

by the way, in silent mode (it is indeed very quiet, perhaps inaudible, but currently, fan on my radeon 8500 is masking any noise the zalman fan may be making).
idle: 33-35*C (room's pretty cold)
loaded with prime95: 48-51*C max.

my cpu is 1ghz p3 w/ 133mhz bus. mobo is asus cusl2.

any inputs on zm80 from zalman?

According to my experience, SLK-800 is no better in passive cooling than Zalman 6000AlCu.

hey old dude. that interests me alot. so you think they're about the same passively? do you have any idle/loaded temperature with passive cooling for either heatsinks? i've done passive with cnps6000-CU (which is supposedly better than ALCU) and it's fine with idle, but 1-2minutes of loaded bumped up the temperature into the warning region.

i'm running p3 1ghz w/ 133mhz bus. what cpu are you running?

thanks man.

The question is why passive? If you are running 3 Panaflos (at whatever speed) in the case already, why not take one of them and put it on top of the cooler? It would mean the same amount of noise but MUCH cooler for the CPU. Unless you can eliminate ALL noise from a PC, there's no point running the CPU HS fanless. Compared to a Panaflo at 5-7V, the difference is really not significant at all in a closed case when there are other sources of noise within it -- the HDD and PSU fan. Now if you can get rid of those noise, THEN passive HS makes more sense.

hey mike,

as always you make excellent observations and comments i really appreciate your work.

that makes sense to me. i have zalman power supply, lian-li pc-61, 3 panaflo L fans, one of those mechano fans coming to me. I'm thinking of getting papst just to compare the fans for you guys.

my final goal will be running only one fan (psu fan) in the whole system. and MAYBE one papst or panaflo over the cpu at very low voltage only if it's necessary with 24hr load. it's obvious from your review that SLK-800 does much better job at passive cooling. and do you think p3 1ghz w/ 133mhz bus will be a good candidate for passive cooling with slk-800?

my reasoning for getting that many fans was to create case air flow with NO noise. i was under the impression that at 5v, they'll make little noise and move about 20cfm. i was doing to do 4v and move 10cfm per fan, which would make no noise per each fan. and to make up for the loss in air flow per one fan, i'll add additional 'silent' fans while keeping the whole system 'silent'. does that make sense? or just too theoretical and not realistic?

ah can't wait until the zm80 hit the shelf hopefully it'll work with my 8500 128mb retail non-le.

I have both heatsinks and run them passively with a XP 1700+ processor underclocked to 7.5 x 133MHz and 1.15V core voltage.The SLK-800's temp actually raised 2C higher, but the trouble is that I don't trust my Soltek SL75DRV5's thermal diode readings so I cannot say for sure.

Anyway, I think one trick in using a Zalman flower heatsink is to position the fan asymmetrically like it's showed in the heatsink instructions. I don't know how many users discover to do it that way because intuitively it feels that the symmetric position would be the right way to position the fan. In my case it decreased the temp by about 2C.

According to the specs, there's only a small difference in Cu and AlCu cooling efficiencys. If the CPU's power consumption is 50W, the difference in the temps is 1C.

cool. that's a good comparison. hmm... now i wonder whether i should ebay slk-800 or zalman... decisions decision...

Again, according to my experience, SLK-800 is clearly better if you use a fan on it. Unlike in MikeC's test, my heatsink did not show such a drastic worsening when putting the Panaflo to 5V. In one experiment, running my processor at XP 1600+, the socket temp was 37C with the fan at 12V and 51C at 5V whereas MikeC got 35C and 58C respectively. Interesting differences!

More like 10 cfm. They are virtually silent at 5V -- if there is no impedance on either side of the fan. Impedance is anything that blocks the airflow, usually a distance of even 1/2" is audibly quieter. This is one reason I recommended the Zalman-style fan mount -- sort of hanging over the HS but not touching it. Ditto cutting away grills from air vents -- on a LianLi, which is so pretty, this would be going against the grain. Also if the airflow is real low (as with 5V) the difference is pretty small.

Noise is additive, somewhat. Two identical 10 dBA fans will make 13 dBA. 3 will make something like 15 dBA. Whether 3 very quiet fans or 1 quiet fan with the same CFM is noisier is really difficult to predict, just have to try it. Main advantage of multiple fans is spot cooling, which still remains extremely useful & usually necessary.

I do have a P3-550 oc'd to 733 and undervolted to 1.45Vcore that I run more or less fanless. There is a 4.5V Panaflo in the elcheapo PSU, a massive GlobalWin VOS32 HS w/o fan, and a 4.5V Panaflo on the back panel, blowing out, very close to the CPU. It's my most stable machine, never crashes despite gazillions of software on it. The CPU generates only 15W heat at this setting.

Whether the P3-1GHz can be run fanless with the SLK800: Stock, it puts out 26-34W depending on which variant you have. For details, look for the link to Processor Electrical Specs under Links, in information sites. Also, go the the Links area, look under software utilities for Radiate http://www.silentpcreview.com/modules.p ... file=index This is a great little software that let's you calculate temp of CPUs based on HS c/w, Vcore, core speed, and CPU type. Lacking the most recent CPUs, but still very useful & fun to play with, extremely educational.

Looks to me if you can undervolt stably to 1.5V or less, you CPU power drops to ~22W and you MIGHT have a chance to cool it passively -- but again, I don't know what you gain against a 5/7V Panaflo.

i think i'm leaning towards this solution:

panaflo directly over the slk800. do panaflo must be undervolted to make them virtually silent? if so, would zalman fanmate do the trick?

zalman psu. does changing the stock fan with panaflo make noticeable difference?

i think that's it. and will wait for zm-80 and ata v 120gb.

yes & yes - very noticeable.

cool. i'll do that.

hey i may be paranoid... but is ZM300A-APF and zm300a-pfc same thing? i've posted in the power supply section too.

yes - they have only model.

hey mike, i'm just curious if you were shopping for the quietest 300w ps, which one would you get?

don't really know. have several PSUs, various makes from el cheapo to expensive -- all modded with Panaflos or NMBs, which usually run ~5-7V. I think I am more silence obsessed than most & perfectly comfortable hacking around inside PSUs, so...

hehe cool..

well how about if i were to say, all i'll do is to change the stock fan to an aftermarket fan? and leave everything alone?

my first utmost priority is also silence, not performance.

i guess what i'm really asking is, zalman or ss-300? they're both on top of your recommended list so i think you'll also find yourself in between those two. well if otherwise, i would like to know... darn this site is kinda addictive...