Temp increase of 15C with 7000B AlCu - Is it normal?

[Denis54]

I have a P4 3.0 (Prescott) with an ASUS P4P800 deluxe motherboard. This weekend, I replaced the stock heatsink with a ZALMAN 7000B AlCu. I am very pleased with the drastic fan noise reduction I get compared to the stock heatsink.

With the 7000B, idle temp is 41 C for the CPU and 34 C for the case. At 100% CPU usage, CPU temp increases to 56 C and case temp increases to 39 C. Is this normal?

This was my first heatsink install and I am not sure I did a good job applying the stock thermal paste I got with the ZALMAN. If my temp increase is too large, should I start over and re-apply the thermal paste? Should I rather use Arctic Silver 5?

I do not want to overclock my CPU.

 

[beatle]

Your case temps are pretty high. Even the best heatsink will struggle in a hot case. What case are you using? What were your temps with the stock cooler?

 

[BonzaiDuck]

Let's do a little numbers-crunchin' with your data.

I know from reviews that the best thermal resistance value for the CNPS-7000-AlCu is a little worse than the all-copper model. That is, it is around 0.22 C/W. Thermal Design Power for a Prescott CPU is around 103W. You would expect a maximum difference between idle and load temperatures of:

0.22 x 103 = 22.7 C degrees

This is worst-case scenario, and you haven't specified how you test load temperature: PRIME95? CPU-Burn? Maybe that value of TDP is for faster Prescotts. Maybe the real value is 89 watts. Then you would expect 0.22 x 89 = 19.6C

In your case, you show about a 15C difference between idle and load, so I can assume your heatsink is "working". You may want to "check" the mounting, the thermal paste etc., but bu-leeve me, brother-man -- your idle-load difference is actually better than it should be. So "Don' lay no big rap up on me-man."

On the other hand, I concur with Beatle -- your case temps are higher than they could be. This shows in your "motherboard temperature" value, which measures an ambient temperature on your motherboard (not, by the way, the chipset temperature, as some may assume). This value is increasing a full 5C or so between idle and load. For comparison, my system with a Northwood 3.0C @ 3.6 Ghz shows only an increase of about 1 to 2C in the mobo temperature value between idle and (PRIME95) load. Anyway, your case interior temperature is a bit high as it is (or "by itself") at close to 93F (idle). This time of year? With the weather we've had all over the lower 48 states? Even in Southern California, my room temperatures haven't been much above 68F for the last two months, guy! And your mobo temperature should be closer to room temperature if you have "excellent" airflow through the case.

 

[BonzaiDuck]

Good motherboard choice, by the way, IMHO. I have read many reviews that suggest -- for some reason -- that particular motherboard model (also mine) results in lower-than-average CPU temperatures. It could be folklore; it could be "fact" with an assignable cause. So I think we know where to look in your system for cooling improvements: focus on air throughput for the case you're using.

 

[Denis54]

I am using a no-name case that was given to me. I have no fan but the covers are off. The case has enough space for one 80 mm fan. I will try it with a fan and see what happens. I doubt this will be enough.

I tested CPU temp by ripping a DVD to the HD. I assumed that this would use CPU at 100% but I was wrong. I just checked and it only utilises CPU at 60%.

I guess a new case is in my near future.

 

[Zucarita9000]

Keep in mind that the thermal paste takes some time to start working, sometimes about a week (it depends on how often you turn your computer off and on).

I have a 7000B AlCu also, and my idle temps as of right now are 39ºC for the CPU and 28ºC for the motherboard.

 

[ImDonly1]

I have a 7000B AlCu with a 2.8E Prescott and a P4P800-E Deluxe. It idles at about 46 degrees when I turn the computer on then when I play a game and then turn the game off and it idles it goes to like 50 degrees. At load it goes to 60 (when playing a game). MB temperature is 34 degrees.

 

[Denis54]

ImDonly1 your case temp at 34 C is much higher than Zucarita9000's at 28 C. He has an Antec SLK3700 AMB. Can you give us details about your case and what kind of fans you have in it?

 

[ImDonly1]

I have one of these in the back http://www.vantecusa.com/p_sf_6025l.html The Zalman on the CPU (7000B AlCu) and that's it.

P4 2.8E 1MB Cache 800 FSB
ATI Radeon 9200 SE
Wireless LAN Card
2 Hard Drives
2 CD-ROMS
Floppy
Asus P4P800-E Deluxe
I run the Zalman are regular speeds I don't use the Fan Mate controller. I just use the q-fan feature. It runs idle at 2100 rpm and at 2600 on load.

The case is from a VPR Matrix Computer. http://www.vprmatrix.com/produ...asp?image=1600_296_392 like that.

The power supply runs hot. If you put your hand behind it. I think that is why it is hotter.

 

[Zucarita9000]

Temps update: Right now, my temps are 41ºC for the CPU and 30ºC for the motherboard. Running a few IE windows, playing some mp3's and ReGet is downloading some stuff.... I would consider this as "low load".

Under medium load, CPU goes at about 44-46ºC, but it depends heavily on room temperature. During hot days, CPU and motherboard temps go up a few degrees. I've seen my Prescott idling at 47ºC!.