Wait for Q9550s or buy Q9550 and undervolt?

E

Ender

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I'm getting tired of waiting for Intel to release the low wattage version of the Q9550 because I just want to build my SFF box. Given that I want this box to have low power consumption and low heat output (will move it to a HTPC role eventually) I want the newer chip with 65W vs 95W.

Should I wait or just buy a Q9550, hope that I get a E0, and undervolt it? Anyone have any experience in doing this? I don't intend to overclock the chip as I think its fast enough stock for what I will be doing.
 
Just undervolt, the standard Q9550 is already a pretty low power consuming CPU (the 95W TDP is somewhat overrated). For data, I have a C1 stepping Q9550 that can be run at 3.1GHz at 1.1v. The E0s are even better in terms of voltage required to hit a specific clockspeed.
 
What exactly is the stock voltage of the Q9550 vs the Q9550s? The specs on Intel's web site have a rather large range...

edit: Intel's site states VID Voltage Range: 0.85V – 1.3625V for both processors... :confused:

I'm guessing that as there is 2 box codes for the Q9550, one is the C1 and the other is the E0 stepping otherwise everything else is almost the same.
 
The VID probably varies from chip to chip like it does for Intel's other quads, so I doubt there's a specific voltage that it's set to.

I did a quick calculation based on the ideal equation for power consumption of a CPU (P=C*[V^2]*f) and my own Q9550's VID of 1.225V, and I came up with approximately 1.013V for 65W of power consumption. I doubt it's a particularly accurate value though, considering that I used 95W and 65W when the actual power consumption of the CPUs is probably a fair amount lower than that, and the fact that the equation is idealised so the actual power consumption is probably affected by many other factors. It should give you a general idea of the voltage range though.
 
So what are the chances of being able to get a Q9550, and undervolt it to ~1.000 in order to get the benefits of the Q9550s without having to pay the price?
 
FWIW, I have been running a Q9450 just below 1.000v VID at stock speeds for about a year now, no problems. It's Prime95 stable 12+ hours.

I am interested in upgrading a SFF system (airflow constrained) from E4300 to Q9550 but I do not want to pay the "S" premium. Would it make more sense to buy a Q9650 for +60$ rather than +103$ for the Q9550S? I would hope to undervolt/underclock the Q9650 until the system becomes cpu-limited after future GPU upgardes. I'm thinking the 9550S and the 9650 binning process may be similar.
 
fwkitziger, do you have any data on temps / wattage draw at the wall of your chip running at stock voltage vs the 1.000 voltage?

I might end up going the 9650 and underclock/undervolt route also but I don't want it to affect memory throughput... I wish Intel would unlock the multiplier :(
 
Ender said:
I might end up going the 9650 and underclock/undervolt route also but I don't want it to affect memory throughput... I wish Intel would unlock the multiplier :(
Click to expand...
It's unlocked downward. You can still underclock without changing the FSB.
 
Ender said:
fwkitziger, do you have any data on temps / wattage draw at the wall of your chip running at stock voltage vs the 1.000 voltage? :(
Click to expand...

For the Q9450, out-of-the-box 1.225 VID pulls 87 watts idle and 153 watts load and the undervolted 0.99375 VID pulls 77 watts idle and 115 watts load at the wall. When the 9450came out last year, there was all sorts of confusion about temps with the new 45nm chips, so my notes are rather confusing as well, but I concluded load max was around 48C undervolted. However, it was such a significant drop, that I am able to run the chip passive-cooled with a Ninja RevB on it. I haven't had one hiccup since and it's a DVD-ripping, shrinking workhorse, plus my sons wear out the Steam catalog on weekends.
 
Ender said:
I'm getting tired of waiting for Intel to release the low wattage version of the Q9550 because I just want to build my SFF box. Given that I want this box to have low power consumption and low heat output (will move it to a HTPC role eventually) I want the newer chip with 65W vs 95W.

Should I wait or just buy a Q9550, hope that I get a E0, and undervolt it? Anyone have any experience in doing this? I don't intend to overclock the chip as I think its fast enough stock for what I will be doing.
Click to expand...

Don't waste your time. http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3505
 
fwkitziger, thank you for the information, its very useful! Do you recall the temps at idle vs load between when the CPU was undervolted and stock? Also the ambient temp if its not asking too much! :)

spectrumbx, I have read the review and am aware of their conclusions... I am ok with paying extra for lower temps and wattage however I can't find the damn chips anywhere. Hence I started this thread, why keep waiting and pay more if I don't have to? ;)
 
My c1 stepping q9550 runs at 1.04V at 2.003 GHz and 1.14V at 2.833 GHz according to lmsensors under linux. I was trying to figure out what the correct values for this and a google search lead me here..
 
fwkitziger said:
For the Q9450, out-of-the-box 1.225 VID pulls 87 watts idle and 153 watts load and the undervolted 0.99375 VID pulls 77 watts idle and 115 watts load at the wall. When the 9450came out last year, there was all sorts of confusion about temps with the new 45nm chips, so my notes are rather confusing as well, but I concluded load max was around 48C undervolted. However, it was such a significant drop, that I am able to run the chip passive-cooled with a Ninja RevB on it. I haven't had one hiccup since and it's a DVD-ripping, shrinking workhorse, plus my sons wear out the Steam catalog on weekends.
Click to expand...

My Q9550 + 3 hard drives + kworld 115 tuner card + 6GB of memory pulls ~95W at idle and 120 to 130W at full load. I am using a fanless nVidia 8400GS. This is according to Kill-a-watt
 
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