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1
NO, you don't need all GPUs on one CPU. Asus supports 4-way SLI over 2 CPUs/PCIe lanes over 2 CPUs.

You're right, there is nowhere mentioning it in the mobo's manual.

NO you should not try to force a 2-way SLI in CPU1 if there is a lot of other hardware attached to that CPU while CPU2 has nothing else to do than pure computation. This was proven by LinusTech in one of his videos where he had build a Video rendering beast (can't find that particular one right now). But the end result was that when GPUs were connected to CPU1 it was slow like hell and after switching to CPU2 the speed improved significantly.

I will take a look at that video. That's interesting.
2
Do not be surprised to have negative reactions with a topic like this on a serious forum and where there are many high-level participants.

To illustrate your fantasy theory, you present a video about Stanley Meyer, a charlatan condemned by the justice ...
Congratulations on your references!

What will be your next topic? The earth is flat? :-DD

Plague yourself with Dave if you want ..... If there is one thing Dave has never hesitated to do is to call a bullshit a bullshit.
And your electrolysis optimization via arbitrary wave forms, it is bullshit.
3
Projects, Designs, and Technical Stuff / Re: The £1.00 atomic clock
« Last post by picitup on Today at 07:40:32 PM »
@bpiphany it sounds like your solenoid maybe had 2 coils?  Mine only has one with the cylindrical magnet between the poles.  Funny you could make your clock go backwards.  There could be a market here.....

@PA0PBZ that's not a silly idea.  I'll give it a try later on today.  I had thought of using a jk flipflop as a divide by 2 then use the normal and inverted outputs to provide the AC voltage but the way you used the capacitor is brilliantly simple.

I also considered using a couple of class B direct coupled amplifier circuits, but that's getting to complicated for a simple project.

The only other idea was to use a pic chip to do:

The frequency / 2
The monostable pulse for the coil
The high impedance output (no connection) for the coil

By using 2 outputs, they could be 1 0 for 30ms, high Z for a second then 0 1 for 30ms, high Z etc.....

After looking on the Microchip MAPS selector, the PIC10F320 looked useful and could be a single chip solution with no external components:

Supply voltage - 2.3 - 5.5v - CR2016 battery?
Internal 31KHz oscillator - no xtal needed
50mA I/O current, so no external buffers
Available in 8 pin DIP package
Cost £2.00

The firmware could be as simple as polling an input pin for change then setting the outputs appropriately, or even better, set an input pin to trigger an interrupt, waking the device from sleep, and that would extend battery life.  Guess I'll see how much time I want to spend on it.  I wouldn't expect the PIC10F320 to draw a massive amount of current at 31KHz.

Well I've ordered a couple of pic chips, but will definitely try your idea @PA0PBZ as I think it has a lot of merit.

I'll report back when I have some more progress.

Cheers

Steve
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Metrology / Re: Warning: !!! Metrology scam !!!
« Last post by TiN on Today at 07:39:37 PM »
I see no misleading here, to be fair. Item description clearly says 509 (STD) board. Photos clearly show 509 board. Seller took the effort to actually take decent pics for each sides, not all do this.
There is no promise anywhere that you get 519 or 529 board. Seller may not know much about 3458A, it doesn't mean listing have a problem though.

Age is a good thing in this particular case, as there is a chance that this reference was aged and stabilized over all those years. If I'd have a choice to buy LTZ ref from 1988 or new one from 2016 for same price and parts otherwise, I'd go for 1988 one. There is high chance that such reference can be more stable than brand new 519 A9 Ref :)

Price is okayish too, you wouldn't get LTZ ref much cheaper even if you do it all DIY.
If you think that getting A9-HFL 2ppm/year board directly from Keysight for 2K$ is much better, and does not need rigorous and time consuming testing with verified equipment - well, you are in for surprise  :bullshit:
5
Jobs / Re: Summer Internship at Electric Imp
« Last post by publicStaticVoidShootMe on Today at 07:32:50 PM »
I'm from Wisconsin but I have family in the Bay area. Here's my resume.
6
General Chat / LC filter increases ripple ??
« Last post by hedley on Today at 07:30:15 PM »
Any help in understanding this will be appreciated
7
Other Equipment & Products / Re: Cheap tools
« Last post by wilfred on Today at 07:19:29 PM »
Do you guys have any recommendations for cheap soldering stations not looking to spend over $100 AUD.
Also a good quality multi meter that is less than $50 AUD.

The UNI-T 61E seems to be a popular choice. But it is nearer $70. There are these threads on the EEVBLOG
http://www.eevblog.com/forum/testgear/uni-t-ut61e-different-versions/
http://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/

The UNI-T UT139C can be had on Ebay for slightly less than $50.

Consider Daves EEVBlog Brymen 235 he sells on Ebay. His "back from Holidays" special seems to have ended (if there was such a thing) but $135 is still pretty good value. For about a week you could save 10 bucks. Maybe there'll be a back-to-school special.

With those budget constraints I would swap them around and get a $100 meter and $50 station. There are plenty of reviews of soldering stations like this one for example that seem to suggest they work OK. But I don't personally use one of them.
http://www.ebay.com.au/itm/New-60W-Weld-Soldering-Station-Iron-Stand-Digital-Temp-Control-ESD-Safe-Sponge-/121902190544?hash=item1c61efcfd0:g:87YAAOSw4shYBs2J
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NO, you don't need all GPUs on one CPU. Asus supports 4-way SLI over 2 CPUs/PCIe lanes over 2 CPUs.
NO you should not try to force a 2-way SLI in CPU1 if there is a lot of other hardware attached to that CPU while CPU2 has nothing else to do than pure computation. This was proven by LinusTech in one of his videos where he had build a Video rendering beast (can't find that particular one right now). But the end result was that when GPUs were connected to CPU1 it was slow like hell and after switching to CPU2 the speed improved significantly.

But don't take my word on this, go find the relevant videos and benchmarks yourself.
9
General Chat / Re: Abandoned places full of old electronics and stuff
« Last post by Brutte on Today at 07:11:23 PM »
But it's missing a "plus a constant, motherfucker".
I'd also take care of that minus, just in case that Bitch passes by.
10
Metrology / Re: Warning: !!! Metrology scam !!!
« Last post by butterfly on Today at 07:10:19 PM »
Hello VoltNuts - although following case is not a real metrology SCAM but professional seller comments are rather misleading - the seller pretends that this Voltage Reference is almost new - to quote in their own words: "Unit is in like new condition. Purchased as an upgrade for existing unit, but was unneeded ..."

http://www.ebay.com/itm/Agilent-HP-Keysigh-03458-66509-DC-Reference-PCA-Board-for-3458A-/252155596302?hash=item3ab5a50e0e:g:djcAAOSw5ZBWOQ1K

1. The date codes on the chips (8844) are very old and contradict the seller's statements - it looks like a HP PCB from the late 80-ies certainly not a recent Agilent/KS PCB.
2. The PCB has a HP badge - the ESD bag indicates the original PCB inside the bag was an (Agilent) HI stability Ref dated 20-6-2011 but the PCB is just a standard REV A 03458-66509
3. Seller pretends that you will receive a PCB that should be an upgrade to what's inside an existing 3458A, upgrades wear 03458-66519 or 03458-66529

For sure the board will work but one needs to have very good equipment to be sure that this board is stable, not a "noisy jumper" or "long term drifter" - only time will tell.

The only use case here is where the buyer knows what he is doing and is going to replace the LTZ chip with a screened (tested) one ... - and the seller - with a professional background in metrology - knows very well that the advertized statements are at least somewhat "over-polished" ...




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