What are safe NB and SB temperature ranges?

[BonzaiDuck]

eVGA 780i motherboard. It's currently over-clocked to:

E8600 @ 4.25 Ghz
FSB = 1,700 Mhz

Most of the voltages were actually trimmed to lower values or kept the same. Only the CPU and CPU_VTT (CPU_FSB) voltages were increased, but within the spec safe range:

CPU VCORE = 1.34V
CPU_VTT = 1.30V
NB = 1.35V
SB = 1.5V (equivalent to the stock "auto" setting)

All other voltages are set at the stock values shown when the board was running at stock settings.

I'd noticed that OC'ing the board (increasing host frequency from 333 to 425 Mhz) also increased the idle NB temperature by about 2 or 3C degrees -- from about 48C to around 50C @ room-ambient 74F. Now that I've added a new version of the Everest monitoring software, it shows the MCP (SB) temperature idle at about the same value -- 50C.

I was running the X-Plane 9 flight-simulator on the system, and had a "marathon" flight from Las Vegas Municipal (New Mexico) to an air-reserve base in So. Calif. So I was "flying" for more than an hour or so.

When I exited the software and checked Everest on a whim, it was showing the MCP at 56C.

This actually persisted for a bit, and I rebooted to check the BIOS monitor. It returned an MCP temperature of around 52C.

I know these chips are supposed to run a little on the hot side.

What is "too hot?"

 

[BonzaiDuck]

Well, about a day has passed on this one, so I'll try and answer it myself. :laugh:

Most people with this motherboard who've tried "enhanced" [air] cooling for the Northbridge/SPP express satisfaction for getting the temperature down to maybe 45C at idle. The SPP and MCP utilize the same heatpipe cooling device installed by the manufacturer, with the "hot" end of the heatpipe on the MCP (Southbridge).

1.5V is about the minimum on the "setting" scale for the MCP.

"Problematic" MCP temperatures reported at different forums seem to be load values exceeding 70C. Other forums and reviews report "normal" values -- idle AND load -- in the 50 to 60C range.

Even these values seem to be of concern to some 780i board-owners, so in addition to NB(SPP) fan replacement, other "cooling mods" are touted by some:

TR HR-05 and hacksaw mod of XFX (eVGA) 780i SPP and MCP

The blog-author reported cutting the heatpipe between the NB(SPP) and SB(MCP) -- so he could install the HR-05 cooler on the MCP Southbridge. He filled the open hole in the remaining stock heatpipe cooler with lead-free solder, noting that he wanted to assure that none of the heatpipe element "leaked."

I'm not so sure modding the stock heatpipe itself was such a good idea, but his temperatures are lower. He doesn't report the resulting temperatures on the NB(SPP) -- a factor essential to evaluating the success of his hacksaw mod. He only reports a SB(MCP) temperature drop putting the thermal range in the low to mid 40's Celsius range. His peak temperature (at my own room-ambient) is only about 10C less than my peak temperature recorded the other day.

I'm not keen on cutting up heatpipes, resealing them, and hoping that they still function properly.

 

[lopri]

Does Everest show SPP temp?

Old versions would show 'true' SPP temp, but on a newer build it somehow disappeared. That was about 6 months ago.

Quad-core CPUs seemed to heat up the SPP more than anything else, from what I've seen. Adding more memory sticks does the trick as well. You really need to 'touch' that thing to feel its temper.

 

[BonzaiDuck]

Originally posted by: lopri
Does Everest show SPP temp?

Old versions would show 'true' SPP temp, but on a newer build it somehow disappeared. That was about 6 months ago.

Quad-core CPUs seemed to heat up the SPP more than anything else, from what I've seen. Adding more memory sticks does the trick as well. You really need to 'touch' that thing to feel its temper.

I try and constrain my hardware configurations based on experience with overloaded systems before. But each new generation provides caveats to the old rules-of-thumb.

I've avoided filling four slots with ram, content with 4GB instead of 8. I haven't tried a C2Q on this board yet, although I have a Q6600 B3 on an earlier 680i board (and that shouldn't differ all that much from this 780i, except for the nForce 200 chip on the latter).

I'm still on a learning-curve with over-clocking, and just two years ago, I left the NB voltages at equivalent to "stock-auto" setting. Now, I've reduced the NB voltage enough to make a difference on the NB(SPP) thermals. But there's not much I can do for the MCP chip.

As I said, given what I'd seen at forums and other sources, these board seem to run their NB and SB temperatures between 48 and mid-50's C under temperatures ranging to warm room-ambients. It may make some slight advantage to reduce the temperatures to the mid-40's, and maybe water-cooling could drop them below that considerably.

But with the current over-clocks I have with an E8600, I'm really not inclined to go after a few more Celsius in "grains-of-rice."

 

[BonzaiDuck]

Originally posted by: lopri
Does Everest show SPP temp?

Old versions would show 'true' SPP temp, but on a newer build it somehow disappeared. That was about 6 months ago.

Quad-core CPUs seemed to heat up the SPP more than anything else, from what I've seen. Adding more memory sticks does the trick as well. You really need to 'touch' that thing to feel its temper.

The latest Everest Ultimate Personal -- v.5.1 I think -- shows SPP and MCP on the 780i board. That is . . . . if you pay for it. The Trial version may restrict showing one or the other, but not both as I recall.