Thinkpads Forum

What is the best CPU to go in the T400? Lenovo lists up to T9800. I read that the chipset supports quad cores, but cooling is not adequate. Any way to make quad core a possibility?

Highly doubt a quad-core would work. I recall a W500 having a quad-core crammed into it with poor results.

All Penryn mobile quad-core CPUs have 45W TDP (Q9000, Q9100, QX9300). T9800 have only 35W.
T400 cooling system isn't designed for that, it's for large size laptops, like W700.

Okay, scratch that then. What about the T9900?

hunterman223 wrote:Okay, scratch that then. What about the T9900?

I'm sure it will work.
Have seen some ebay auctions for T400 with T9900 CPU, for example http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0212937647

That would be great then. It turns out the T9900 is cheaper than the T9800 on eBay UK.


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Lucky you. I'm still here with a P8700. Remember to undervolt!

Colonel O'Neill wrote:Lucky you. I'm still here with a P8700. Remember to undervolt!

T9400 at the moment, considering upgrading. Why underfoot? Don't the T9400 and the T9900 have the same wattage? You're the lucky one, P series = better battery life.


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For whatever reason, I can manage six hours on my six cell on a very freshly installed system. Once I start installing stuff, it drops to three and a half hours.

You can drop the voltage on T CPU's more I think; my P8700 is limited to 0.8750V. SuperLFM, 6x, and 7x are all bottomed out at 0.8750V.

How much does undervolting affect performance? And his much of a benefit does it bring with it?


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Undervolting doesn't cause any performance decrease, but may provide a performance increase by preventing the chip from being thermally throttled.

It decreases temperatures and increases battery life, that's about it.

Sounds alright to me. What program do you use for that? I assume it's the same as overclocking, trial and error to find the lowest voltage?


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I'm using RMClock, which is the program of choice for most.
And yeah, it's pretty much the same procedure along with all the stress testing (IntelBurnTest works great here).

Thanks. Before you mentioned undervolting increases performance by preventing thermal throttling. Does that really occur that often?


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Not for mine, but the T CPUs tend to run hotter by default.
However, when I overclock my GPU, games stutter after my machine heats up unless I set my fan to level 64.

Alright thanks, i'll play with some voltages and let you know.


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After some 10 minutes of use at 2.93GHz in my second hand T400, I can heartily recommend the Intel E8335 SLGEB that salvaged from iMac starts from ~$110 on ebay with specs similar to T9800:

http://valid.canardpc.com/show_oc.php?id=2420198

Beware of the other Intel E8335 that is not SLGEB, it seems to suck. Safest to search ebay for just SLGEB. Luckily this name seems unique to the good part =)

CPU runs at 2.93GHz with spec thermal output of 35W and 6M cache and best of all it even has VT!

Wow, that's great. I was actually wondering not too long ago if that particular CPU would work..

Would you mind running WEI with the new CPU? My T9400 scores 6.1, or 6.2 if IDA is enabled with RMClock.

Edit: Another question about the swap itself, does the T400 use a thermal pad or did you need to repaste the new CPU yourself?

Hi,

Would you mind running WEI with the new CPU?

sorry to disappoint here but I'm running Windows Server 2008 R2 on the laptop and getting WEI to run on the OS seems a bit complex.

hunterman223 wrote:Another question about the swap itself, does the T400 use a thermal pad or did you need to repaste the new CPU yourself?

I think the northbridge had a thermal pad that came off in potentially salvageable shape while the CPU and GPU had thermal paste.

To not have to think about anything, I cleaned off all the old stuff including the pad and applied some Arctic Silver 5. Reusing or replacing the thermal pad would probably have been more professional not to generate a gap between the northbridge chip and the heat sink, instead I just used somewhat too much AS5 stuff where the pad used to sit and slightly bent the metal springs holding that part of the heat sink for added tension and pressure. The result is completely stable in spite of this corner cutting.

That's alright about WEI, I can find my own benchmarks.

A couple weeks ago I repasted my T9400 with AS Ceramique, I replaced the thermal pad with one from Frozencpu.com. I think it was a Fujipoly, I just measured the thickness of the old pad and cut it to length and width. Worked great. Your method would have saved me $5 though.

Interesting ..
Any comments about the heat over the HD area?.
I have a old T400 with p8400 , 4gb , 160 GB,wxga+....

T400plus wrote:Interesting ..
Any comments about the heat over the HD area?.
I have a old T400 with p8400 , 4gb , 160 GB,wxga+....

Are you asking about heat over that area in general?

It depends on the drive you have installed. Nothing else is there that will heat that area up besides the hard drive. It used to get warm with a 7200 rpm drive, room temp with a Crucial M4 SSD, hot with a Vertex 4 SSD, and right now with the interim 5400 rpm drive it is slightly cooler than the 7200 rpm drive. We'll see how the Samsung 830 does when that arrives.

Thanks.
The HD is the one which lenovo canada dumped me with(3 yearsback ).I think it is 160 GB 7200 rpm.
Are SSD drives also heat radiating?

SSDs do produce heat, some more than others. The Vertex 4 used quite a bit of power and produced quite a bit of heat for an SSD, likely due to the powerful controller. I have read that it uses a partially metal casing to act as a heatsink for the controller, hence why one side of the laptop (the top) was hotter than the other side.

If you look at reviews on Anandtech you can find out which drives use the least power, less power should = less heat + better battery life.

I'm rocking a 256GB Samsung 830 SSD in my T400. The area underneath the right palm (HDD) is really cool; never really gets toasty. If you select this SSD, you are good to go.

hunterman223 wrote:
Are you asking about heat over that area in general?

It depends on the drive you have installed. Nothing else is there that will heat that area up besides the hard drive. It used to get warm with a 7200 rpm drive, room temp with a Crucial M4 SSD, hot with a Vertex 4 SSD, and right now with the interim 5400 rpm drive it is slightly cooler than the 7200 rpm drive. We'll see how the Samsung 830 does when that arrives.

Thanks, that's good to hear.

Seller told me it was shipped the same say I bought it, (more than 1 week ago) saying he would upload tracking later. Well he did, a week later. And that same tracking info informed me that it had not even been accepted into the UPS system.. /rant

Anyways, hopefully the drive will have been worth the long wait...