Pentium D 805 Overclocking

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With Intel’s retail heatsink and with Thermalright’s Ultra 120 – Joe

SUMMARY: The Pentium D 805 is a very well-behaved overclocking CPU.

I received emails asking about overclocking the Pentium D 805 – I thought what might be interesting is to see how well it does “at its worst”, which I’ll define as using nothing more than the heatsink that Intel packs with it and all settings at spec EXCEPT for changing FSBs.

The Test

I ran this series on an Asus P5WD2 motherboard P4 Motherboard Test Platform with a modified Pentium D 805 to read CPU case temps (both supplied by Directron). I used Asus’s AiBooster to vary FSBs; all testing was with Intel’s retail heatsink and NO change in any voltages – all at spec. I used Prime95 to stress the CPU.

Intel Retail Heatsink

Case Temp

Ambient Temp

Delta

On-Die Temp¹

140 FSB

49.7

27.6

22.1

59

150 FSB

50.1

27.5

22.6

60

160 FSB

51.6

27.6

24.0

61

170 FSB

52.5

28.0

24.5

62

180 FSB

53.6

28.0

25.6

63

190 FSB – FAIL

 

 

 

 

¹MBM on-die temperatures.

This is a pretty minimal temp rise – only 3.5 ºC from 140 to 180 FSB. While 190 FSB proved to be a bridge too far at spec settings, running at 170 or 180 FSB with literally no effort is impressive.

CONCLUSIONS

The Pentium D 805 is a very well-behaved overclocking CPU. With absolutely NO EFFORT, I was able to get a 29% performance boost with nothing more than changing FSBs using Asus’s AiBooster. Consider this a baseline – with better cooling and some tweaking – who knows? Nice chip Intel!
{mospagebreak}

After trying to see how far we can get with Intel’s retail heatsink overclocking the Pentium D 805, a try with Thermalright’s Ultra 120 was in order to see what excellent cooling will do.

The Test

I ran this series on an Asus P5WD2 motherboard P4 Motherboard Test Platform with a modified Pentium D 805 to read CPU case temps (both supplied by Directron) cooled Thermalright’s Ultra 120. I used Asus’s AiBooster to vary FSBs and Prime95 to stress the CPU.

Thermalright Ultra 120 Heatsink

Case Temp

Ambient Temp

Delta

On-Die Temp¹

140 FSB

35.1

24.5

10.6

44

150 FSB

35.8

24.8

11.0

45

160 FSB

36.3

25.0

11.3

46

170 FSB

37.2

25.3

11.9

47

180 FSB

37.7

25.5

12.2

47

190 FSB – 1.34 volts

38.5

25.5

13.0

49

200 FSB – Windows Balks

 

 

 

 

¹MBM on-die temperatures.

This is a pretty minimal temp rise – only 2.4 ºC from 140 to 190 FSB with a minimal voltage boost to reach 190; absolute temps are also quite a bit more reassuring than with Intel’s heatsink. While 200 FSB proved to be a bridge too far for Windows XP, running at 180 or 190 FSB with literally no effort at very reasonable temps is impressive.

CONCLUSIONS

The only bar to running this CPU further was Windows – seems like XP does not like high FSBs. Too bad as no doubt there is headroom in this CPU to go further – a tweaker’s dream!
{mospagebreak}

I’ve been checking out Ultra-X’s RST Pro PCI Express ™ by running it on an Asus P5WD2 motherboard P4 Motherboard Test Platform with a modified Pentium D 805 to read CPU case temps (both supplied by Directron), trying out some Ballistix DDR2-800 I bought from Crucial.

In my earlier runs with this setup, I found that I could not get close to 200 FSB as Windows balked – I could boot up but not into Windows. Running this setup without an OS getting in the way was an idea and with Ultra-X’s RST Pro PCI Express ™, I had the means to do this with some stress testing.

I used a Thermalright Ultra 120 to cool the CPU as it does an excellent job for an air-cooled heatsink. The Pass or Fail indicates when the RAM would not pass the RST Pro PCI Express ™ stress test.

The results were somewhat better than what I could get with Windows XP:

Thermalright Ultra 120 Heatsink

Case Temp

Ambient Temp

Delta

O/C Result

190 FSB – 1.325v CPU

35.1

24.5

10.6

PASS

198 FSB – 1.325v CPU

36.6

24.2

12.4

PASS

199 FSB – 1.325v CPU

na

na

na

FAIL – Reboots

200 FSB – 1.35v CPU

37.3

25.3

12.0

FAIL – Reboots

Impressive!

Considering that I did not change CPU voltage all that much, the temps are outstanding – not even near hot – the Thermalright does the job nicely. I did get some temp readings before the system went into spontaneous reboots at 200 FSB and they are similar to what I saw at 198 FSB. I got to 180 FSB with Windows XP at spec voltage, so in comparison I was able to get to 190 at spec voltage and to 198 FSB with a little boost.

Conclusions

Damn impressive – an almost 50% increase in speed with not a lot of effort. For the money, the Pentium D 805 is tough to beat, considering that increases of 30% are achievable with spec cooling.

Email Joe

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