Maxing out Dell XPS 435MT

It's that beige box on your floor. In 1999.
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kevm14
Posts: 14577
Joined: Wed Oct 23, 2013 10:28 pm

Maxing out Dell XPS 435MT

Post by kevm14 »

As I have written elsewhere I bought this computer as refurb from Dell in June 2009 for under $700. It was a Core i7-920 with, uh, 4GB RAM, 750GB, and some other specs.

I have since done the following:
- Upgraded PSU when it died
- Added boot SSD (180GB Intel 520)
- Upgraded HDD from 750GB (it died) to a 4TB HGST
- Upgraded RAM several times. Latest is 24GB which may be the most it can handle, but maybe not. It's plenty for what it is anyway.
- Upgraded GPU. Adam gave me his old nVidia 8800GT. Originally was an ATI Radeon HD4670.

I have learned that the best CPU I can drop into this board is a Xeon W3580 which is the Xeon version of the i7-975. It should provide something around a 25% boost to CPU performance which is worthwhile. These old CPUs are available on eBay for $30 or less. I made an offer on one. We'll see.

I also tried my hand at SetFSB and also checked CPU temps running Prime95 to baseline. I am going to run the stock CPU cooler. Fully loaded it goes from mid-40s idling to like a peak of 72C or 74C when slightly overclocked. This should be fine. The overclock is more of an academic exercise. I will probably not really do this long term. Plus I have to use SetFSB so it has to be done each restart. Probably only provides a couple % improvement. Not worth it. If I jack up the FSB beyond a certain point the machine instantly locks up. So again, not worth screwing around for a tiny gain. Upgrading the CPU will be a big gain.
HWmonitor max from prime95 and OC.PNG
For the record here is the setting in SetFSB that seemed to provide the highest core speed running Prime95:
SetFSB max core loaded 2.859GHz.PNG
Room temp was around 67F at the time.
kevm14
Posts: 14577
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxing out Dell XPS 435MT

Post by kevm14 »

Successfully made a task in Task Scheduler to run SetFSB on reboot or wake. This is so marginal but it's "interesting" so I'll stick with it until I get my new CPU. Still waiting for eBay seller to respond to my $23 offer. That could save me $7!
kevm14
Posts: 14577
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxing out Dell XPS 435MT

Post by kevm14 »

I bought it now for full price. $35.29 all in. Still seems like a no brainier. 11 years ago this processor cost $1,059!
kevm14
Posts: 14577
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxing out Dell XPS 435MT

Post by kevm14 »

I disabled the 3MHz FSB overclock for now. Questionable results from an internal CPUz benchmark revealed practically no change, but it completes in under a minute so it may not be the best benchmark. I could try others as this doesn't even seem to register the theoretical 2.2% improvement I should have seen.

Stock
Dell i7-920 CPUz benchmark stock clock.PNG

3MHz FSB overclock.
Dell i7-920 OC FSB by 3 MHz.PNG

Multiplier is 20x so that gives me ~60Mhz of actual overclocking. This is laughable and pointless. If I crank up SetFSB any higher, it instantly freezes the system. It's not worth bothering with. I may tinker with the Intel XTU and changing multipliers when I get my Xeon but for this multiplier locked 920 (on an OEM motherboard), this is pointless.
kevm14
Posts: 14577
Joined: Wed Oct 23, 2013 10:28 pm

Re: Maxing out Dell XPS 435MT

Post by kevm14 »

Decided to open up the Dell and dust it out before doing CPU replacement. It wasn't that bad but there was definitely some in there. I use the air compressor in my garage (carefully) which is 1000x better than a stupid can of compressed air.

New CPU. I cleaned it off with alcohol (after taking this).
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The heatsink is right there. Good case design because the blast of hot air from the CPU is aimed directly at a case fan (which is throttled by the motherboard) and it exhausts the hot air from the case before it has a chance to circulate. I remember the ducted fans of the old Dell Optiplex P4s. I guess this doesn't need that.
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4 screws and the heat sink comes off. Just unplug and remove. Easy.
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This is better quality heatsink than I expected.
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Exposed CPU slot.
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Cleaned heatsink.
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A dab of thermal compound I had laying around (maybe from the Vaio's CPU upgrade now that I think about it), installed the heatsink, put case back together and BAM, success!
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That was really easy. Cinebench reveals a nearly 26% performance improvement from the old i7-920. So great success!

I have also been playing with the turbo multiplier settings in Intel Extreme Tuning Utility (XTU) and while I had some success, I'm not sure the results are worth it based on initial testing....I will experiment more at some point. But running stock is probably fine anyway.
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