A Look at the DIY Upgrade to the Processor on a Dell Notebook

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by Kevin Giberson

I recently upgraded my notebook’s CPU, replacing the T2400 Core Duo processor that came installed in the Precision M65 with a T7600 Core 2 Duo. What follows is a general description of the upgrade, which should also apply quite directly to the Dell Latitude D820, a notebook almost identical to the M65, aside for the GPU. The steps and precautions would likely apply to a variety of other reasonably current notebook computers, as well.

That said, there are certain risks involved with a CPU upgrade, and I’m certainly not advocating that anyone do this. I doubt I would have done the upgrade myself had I not been able to find the following: 1) an abundance of helpful information related to notebook CPU replacement and installation, information often generously and graphically provided by members of this site’s forum community; 2) the notebook service manuals that Dell typically makes available; and 3) the exact CPU I wanted for a price considerably below retail.

Anyway, before clicking the Buy It Now button and committing to the purchase of the T7600, I spent a good deal of time asking myself whether or not the CPU swap was worth the cost, the risk or the trouble.

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The Cost

In many cases the cost is prohibitive or simply doesn’t make sense, particularly in view of the prices of brand-new notebook computers.

Though an objective answer to the question of value is impossible, I first considered how much I like the M65. There would be little reason to spend nearly $400 on an upgrade if I were planning to get rid of the machine within a year or so. (The actual cost of the upgrade was $385, including shipping: $365 for the CPU, which I bought from a reputable eBay seller, and $20 to get a replacement heatsink from Dell.) Once I’d decided that I’d probably keep the M65 for at least a couple more years, I looked at what the upgrade would provide and could name two things: improved performance due to higher operating frequency and more Level 2 cache, and 64-bit capability. Of these improvements, the most appealing was the improved performance, but there’s also a chance that 64-bit support will be worthwhile during the time I own the notebook.

One thing I do know is that I would not have made the switch from a T2600 Yonah CPU to the T7600 Merom, nor would I have bothered swapping out a T7200 Merom for a T7600 Merom. These upgrades would probably not offer enough performance gain to justify the cost, at least for me, though the first switch would at least provide 64-bit compatibility.

In the end, the reason I sprang for the T7600 (and the heatsink) was because of two distinct and meaningful improvements, and the fact that I was able to purchase the unused CPU from a trustworthy seller for a good price. I could not have justified paying a whole lot more when the notebook’s current value would not exceed $1,000.

The Two CPUs (with significant differences in bold)

	Old	New
Name	Yonah T2400	Merom T7600
Number of Cores	2	2
Model	T2400	T7600
Frequency	1.83 GHz	2.33 GHz
FSB	667 MHz	667 MHz
L1 Cache	32KB + 32KB	32KB + 32KB
L2 Cache	2MB	4MB
Manufacturing Process	65nm	65nm
64 Bit Support	No	Yes
Series	Core Duo	Core 2 Duo
Socket	M	M

The Risk

I suppose the main risk for me was voiding the nearly two years of warranty coverage that remains on the M65, though I have never bothered to answer a number of questions regarding the warranty. If the LCD fails, for instance, will Dell tell me that it’s no longer covered because I disassembled the notebook, including detaching the LCD from the video connector on the motherboard? I don’t know, and I’m just hoping I don’t have to find out. Another obvious risk was rendering useless a computer upon which I depend. But thanks to all the online help, I wasn’t overly concerned that I would break anything, and my only real worry was increased heat.

The Primary Risk: Heat

I knew from desktop experience that it was very important to correctly install the heatsink, or Processor Thermal-Cooling Assembly, as it’s called in Dell’s service manual. The heatsink sits atop the CPU, the Memory Controller Hub (MHC) and the graphics chip, so its installation is key to avoiding thermal shutdown and destruction. A number of people recommended cleaning and reusing the existing heatsink, applying Arctic Silver thermal compound at the time of reinstallation, and while this probably works well enough (Arctic Silver is certainly an excellent product), I opted to keep everything stock simply because it’s a little simpler to do so, and perhaps a little less likely to void the warranty.

The Trouble – The Actual Upgrade

The upgrade itself was really no trouble at all, thanks to the service manual and the helpful numbering of screws, especially for the heatsink. I did make sure to update the BIOS before I began.

Working slowly and carefully, the disassembly, CPU swap and reassembly took about an hour. There were a total of 28 screws to remove and replace, and I labeled these as I removed them. A number of components had to be disconnected then reconnected during the reassembly: keyboard, wireless antenna, graphics cable, speaker and touchpad.

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Before putting everything back together, I took the opportunity to give the notebook’s interior a little compressed-air cleaning (as illustrated in recent articles on this website) and used high-purity isopropyl alcohol and Q-tips to clean the MHC. The actual CPU swap involved nothing more than loosening the ZIF socket by turning a single screw, popping in the T7600, turning the screw the other way, and installing the new heatsink.

Motherboard base and heatsink. (view large image)

One thing I found interesting was that the old heatsink showed direct contact between the CPU and the heatsink’s thermal pad, and this was also true of the MHC, but the GPU did not appear to have made direct contact with the blue pad installed on the heatsink; this blue material was utterly pristine, leading me to think that the GPU heat dissipation has little to do with the heatsink, at least in the case of the M65 and its NVIDIA Quadro FX 350M CPU.

The old and new heatsinks. (view large image)

A view of the motherboard with the old CPU without the heatsink. (view large image)

First Boot

Everything started up quickly and without any problems, so quickly, in fact, that I missed my chance to go into the BIOS as I’d intended. There was no discernible difference, other than speed, between starting up with the T7600 the first time and the countless startups I’d experienced with the T2400.

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Temperatures

As mentioned, heat was easily my biggest concern. Others’ experience, and to some extent common sense, told me the T7600 would run hotter than the T2400. For stress testing and temperature monitoring, I relied primarily on the software tools in the table below. These programs, which by no means represent a comprehensive list of what’s available and useful, are all easily downloadable and free:

Software	Purpose
Prime95	Stress the CPU
Core Temp	Display CPU Core Temperatures
EVEREST Home Edition	General Hardware Monitoring
ATITool	Stress and Monitor the GPU

A temperature comparison (all values are Celsius) revealed the following:

Component	Yonah T2400 (Before)	Merom T7600 (After)
Core 0 – Idle	45	43
Core 1 – Idle	40	43
Core 0 – Load	67	75
Core 1 – Load	67	75
GPU – Idle	42	53
GPU – Load	75 – 82	73 – 84

So, as far as I could tell, everything was in order. The above temperatures are fairly representative of the before and after picture, and while the core temps of the T7600 are higher under load than those of the T2400, they are in line with what I expected and the data provided by Intel. There has been no instability and no unexpected shutdowns have occurred. Moreover, I can run multiple applications all day long and core temps generally remain in the high 30s to low 40s Celsius, which seems good. GPU temps are essentially the same as before.

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Performance

So what did I get for my $385 and several hours of surfing the Internet to make sure I didn’t screw anything up, along with a couple of hours of actual work? Well, boot time seems significantly reduced, though I unfortunately didn’t measure the “before” time, so the “after” (or current) time of 20 seconds or so doesn’t mean too much. There has been about a 20% increase in performance as measured by PCMark05, and a Super Pi run to two million digits dropped from 1m 21s to 0m 55s, slightly better than a 30% improvement. Overall, things do seem quite a bit zippier (though the 3DMark06 score for the Quadro 350M is still pretty abysmal).

Benchmark	Yonah T2400 – Before	Merom T7600 – After
PCMark05	3482 PC Marks	4522 PC Marks
3DMark06	691	705
Super Pi	1m 21s	0m 55s

 

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Was it worth it?

It’s early yet, but I have no regrets about the upgrade. I reviewed the M65, purchased from Dell Outlet, for this website a little over a year ago. Although I’ve always been happy with the notebook, the Core 2 Duo Merom was released right around the time of my purchase, and I found myself envying the 64-bit capability and additional L2 cache, and I’d always kind of wanted a faster CPU. At that time, I knew that it would be possible to upgrade from the T2400 to a Merom but was in no hurry to do so. After recently building a midrange desktop computer, however, I began to find the M65 rather slow. This CPU upgrade, including heatsink replacement, was very little trouble and, thanks to a fortunate eBay purchase, was done at a fraction of the cost of a new business-class notebook. So the T2400 to T7600 upgrade made sense for me.

Reasons to Upgrade

• 64-bit capability

• Better overall performance

• Fairly simple to do

• Can extend the useful life of a favorite notebook

Reasons Not to Upgrade

• May well void the warranty

• Minimal performance gain if going from a fast Yonah to a Merom, or a mid-range Merom to a high-end Merom

• Merom retail prices are high (much higher than comparable Santa Rosa CPUs)

• This upgrade is from one non-current CPU to another non-current CPU

• Improper heatsink installation, especially, will cause problems

 

Spectacular job!
I have the previous model, the M70, and wish I could swap into core 2 duo but I am pretty sure mine wont do.

 

Very nice work. Thank for publishing your results.

 

Thank you for the article, interesting read indeed.
So I have concluded, that the gain in performance is so minimal that I don't think, I ever chance my CPU, unless I can change my GPU first, but the overall cost of change both GPU and CPU would probably exceed the price of a new laptop. =D

 

Thanks very much for all the comment.

As the Precision M70 illustrates, a lot of the best upgrades (going from a Pentium M to a dual-core CPU, say) just aren't possible, which is too bad because many of these are great notebooks that probably don't need much besides a CPU boost.

I'd say it's a very narrow range of CPU upgrades that, even if possible, make any sense at all, and I'm sure some people could argue pretty convincingly that my upgrade didn't fall within that narrow range. But, as I said, I really like the M65 and plan to keep it for some time, and it didn't cost that much to begin with because I got it from Dell Outlet. As people generally say, RAM and the hard drive are usually the first things to look at.

Putting aside things like voided warranties and possible damage, it seems to me that almost all upgrades are very tricky from a cost-benefit perspective, with CPU and GPU upgrades (which are pretty rare and often not even possible) being especially so.

 

The M70 did provide one of my favorite upgrades however, an underclocked 7800 GTX from the XPS M170 fit in with some effort to provide an unbelievable 15.4" gaming experience.

 

Very interesting and well-explained.

Has the CPU change had any effect on the battery life?

John

 

Very well presented. You did a nice job explaining your rationalization for upgrading.

I find myself lusting for new and improved hardware often, but I've learned (the hard way) to act more prudently. Articles like this help me to vicariously enjoy the experience without shelling out a bunch of dollars.

One template for the upgrade process looks like this: 1) stay put, 2) upgrade, 3) new system. As you explained, 2) often doesn't make sense. Between 2) and 3) it's sometimes overlooked the time cost for migrating all your data and system settings to a new computer.

Upgrading (usually) lets you keep your HD just the way it is, thank you. Migrating might be fun for some (like me), but it's still an important time sink. I like that you mentioned the significant hours you spent researching the project. They were worth it.

 

I am so glad I only have to remove nine or so screws on my S96J to upgrade the CPU.

Asus barebones FTW!!!

 

Thanks for the additional remarks.

Regarding battery life: very good point, John, and I'll provide some info on that once I test, though the 6-cell is a lot older than when I did the original review.

Those were some great points, danny_8. I really need to keep the upgrade impulse in check, though I often just give in. Also, I kind of like to avoid the whole software reinstallation drill required when I buy/build a new computer. I find it really time consuming to get everything to my liking.

Didn't know the M70 could take a 7800GTX. Impressive achievement, as is making the CPU available with the removal of only 9 screws.

 

In response to your comment about the heatsink: the M65 shares the same heatsink with the D830. I took out my D830's heatsink, intending to replace the stock thermal "stuff" with AS5 and much to my dismay the gap between the sink and the chipset was too wide to fill with anything than the blue pad provided. The gap between the sink and the NVS140 was only slightly smaller.

 

Interesting comments, Commander Wolf.

So I guess Dell didn't change the heatsink when the move was made to the Santa Rosa D830. Not too surprising, I suppose, since The D820/M65 looks just like the D830/M4300.

I didn't want to dwell on the heatsink in the article, but it was all kind of fascinating to me, because at first I thought, "Okay, fine, I'll just clean it off, use some AS5 and that'll be that." But when I read a post or two and saw some good pictures of recent Dell heatsinks, it seemed that the elevation of the CPU, GPU and MHC were all different, meaning direct contact would depend on the blue-filler-thermal-pad, except in the case of the CPU, the tallest chip on the board.

I'm still guessing Arctic Silver would have worked on the D820, at least for the CPU, but the MHC would have been tricky, and because of the whole issue of heat dissipation in laptops (some models seem to have widespread problems), keeping things stock was preferable to me, rather than trying to shave off a couple degrees from the core temps.

Hope you got it all sorted out.

 

I wonder if I can do this on my T60 with the same T2400 Yonah. I'll look into this. Maybe this can save me from having to get a whole new laptop.