Overclocking the goold olde T3500...

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I always thought there was no way to overclock the Xeon due to locked msr in Bios, but tonight I found I can ramp up my W3680 to over 4,2 Ghz just using clover.

This seems to improve rendering times by some 25-30% ! (Geekbench3 bump from 14000 to over 17000). I`ll strap an extra fan onto the cpu and do some testing. 

I never thought this was possible - has anybody tried this too ?

If it doesn't fry it this will be a solid upgrade for zero Bucks (well, a fan...) and Mojave 10.15.6 seems to work really well with the T3500.

 

For Catalina we might need a different smbios one day (using MP 5.1 still here);

has anybody had success using something else ? - all I tried (MP 6.1, iMac 13-14 etc.) made my Geekbench drop to 6000 Points.

 

Best,

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[Hervé]

Yes, I remember playing with similar things with Clover on my old Latitude D630 years ago. @Bronxteck, do you remember?

 

You probably simply increased the declared bus speed and, whilst it seems it can provide overclocking, it actually just affects the reported CPU frequency. I remember going all the way to ridiculous fake speeds (like 6GHz) and the laptop would still boot but it clearly was not running at 6GHz! Anyway, quite rapidly, the laptop stopped working properly. It's no proper or real o/c as far as I'm concerned (else we'd all be doing it!).

 

Slice explained here how GeekBench computes its score so, naturally, the higher the bus speed you declare, the higher the score. But it's kind of fake... If you wanted to verify if you have overclocking or not, you need to do some real comparative application performance measurements, not just rely on GeekBench.

 

More info on the Clover CPU settings here if you want. On my side, I always set the bus speed so that the CPU speed is properly reported in "About this Mac": for instance, setting bus speed of a Sandy Bridge/Ivy Bridge/Haswell/etc. at 100kHz will lead to a reported speed of, say, 2.7 or 3GHz, rather than 2.69 or 2.99GHz. But it really is more cosmetic than anything else.

 

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Thanks Hervé,

 

yes its only FSB so far, but it seems to work first try, and for the whole system.

( I ran a render test file and it went from 52seconds (Stock 3.33ghz) down to 35 seconds (at around 4,2ghz).

That would be quite an improvement for my work, as I was already thinking about buying a new machine; but I have to say I really love the T3500.

 

Do you have knowledge about the other settings available, like :

busratio=xx

undervolt step

min/max multiplier ?

(And the smbios for Catalina ?)

 

Thx

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[Hervé]

Rest assured it's no real or proper overclocking: I've just run my E6230 fitted with an i7-3540M @3GHz with a configured bus speed of 200kHz (i.e. twice the normal CPU bus speed); Booted up Ok and reported a CPU speed of 6GHz ("About This Mac" maxed out @4.3GHz) with Turbo speed up to 7GHz when running GeekBench; it never crashed. Do you think my little mobile i7-3540M really ran at 7GHz? I could probably declare a 300kHz too if I wanted.

 

 

 

 

If it pleases you, stick with your "overclocking" settings. You certainly won't break anything.

 

For the rest, read up the info posted at the link I posted previously or consult the Clover Wiki. For Catalina, I guess you ought to try MP5,1 or MP6,1.

 

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Thanks Hervé,

 

I really don't care about Geekbench or "about this Mac" numbers, just looking if I can improve rendering speed a bit.

Thanks for the link and I`ll try out some more options as mentioned.

MP6,1 should work for Catalina but I have struggled getting it to boot due to the GFX1/blackscreen issue. (also: Nvidia...)

I`ll try adding an extra ssdt for GFX injection for the T3500 to fix that for MP6,1.

 

Thx

[Hervé]

You could try iMac13,2 or iMac14,2; those had nVidia GPUs.

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I clocked the T3500/W3680 up to 4,17Ghz, and I believe it does effect performance/rendering, so far no instabilities or dropouts - we`ll see.

The values I tested are: 3.33 (Stock), 4.17 and 4.4 Ghz (just for a try).

I`ll see how stable this is @ 4.17 now.

 

3.33 Ghz

Geekbench3 14.500

Cinema 4D 1673pts

 

4.17 Ghz

Geekbench3 18.000 

Cinema 4D 2088pts

 

4.4 Ghz

Geekbench 3 19.000 

Cinema 4D 2231pts (as "about this Macs" tops out at 4.3Ghz cinema shows the remaining 0.1Ghz here...funny)

 

For 4.17Ghz set clover/CPU "Bus speed kHz" to 166660, that's all. (Base Multipler for W3680 is 25, I had no effect trying to add the "bus ratio" flag)

No luck with other smbios`s also, (Performance down 50%; same with iMac 14/15/17/18 and MP6.1 incl. ssdt for GFX1)

Try at your own risk - don't forget to strap a 80 or 90mm fan onto the CPU cooler beforehand ! (This seems to be a good idea anyway, even for stock speed).

If you have a different processor this value will not work !! Find out your FSB-multiplier and calculate it...(and find out if your CPU is "unlocked" in the first place !!!)

 

So much for that experiment; does not turn it into a intel Platinum 8186 but its (as always) just for the fun of it (and seems to reduce some render time too...)

 

Thx

 

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