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Charge Apple computers bought in USA to use in Europe

I bought an Apple MacBook in the US and would like to use it in Italy. On the cable, it says: 2.5A 125V. What are the possible solutions to charge my computer? Use an adapter, a plug converter or an electric transformer? Someone can explain to me in details? In Italy, the voltage is around 220V, does it damage my pc if I use only a plug adapter?

I have a 3.3 Volt PCI ethernet card working on a 5 Volt PCI slot. How is it possible?

This is the design for PCI slots:

As you can see, there are 32/64 bits and 3.3/5 Volts.

For what I know:

• 32 bits PCI cards can work in 64 bits slots of the same voltage.
• 64 bits PCI cards can work in 32 bits slots of the same voltage.

I don't have an exact image, but this one I have found on internet is very close to the mine (mine has 4 RJ45, not 2) and shows how some of the PCI contacts can stay outside of the slot, and the card will work OK (maybe at a lower speed):

But I have found something strange in a computer (network server) inside an office: a 64 bits 3.3 Volts ethernet card running (working) on a 32 bits 5 Volts slot.

The card is a Quad Ethernet PCI-X 64 bits:

5740 IBM 03N5444 Quad Port 10/100/1000 Base-TX Ethernet PCI-X Ethernet Adapter

As shown in the PCI design image (see above), a 3.3 Volt PCI card should never fit in a 5 Volt PCI slot, as long as there is a notch (lock, latch or whatever we call it) so the card will never fit in the wrong slot.
But it seems that Attila the Hun was playing with this computer, because the card fitted in the slot. The trick has been to perform a simple cut, as shown in this image:

This is the photo of the surgery-affected card (sorry, my camera is not very good) :

Beside the funny thing of that trick, what is really awesome for me is that the card is working. And, according to employees in that office, it could be working perfect: the server is dedicated mostly to network traffic, a balance load of 3 DSL routers to 3 different LANs. Even when LAN traffic is very low on that office, there is a lot of internet traffic some days (maybe more than 100 users), so the 4-RJ45 network card should work in a rather intensive manner, or so I think.

I don't know for how long this server has been working with this Frankenstein network card (you know what happens in modern enterprises: everybody is a temporal worker :-P, so they can not tell me), but months at least, maybe more.

So, I have two questions:

• How is this possible? Why a 3.3 Volt PCI Card running on a 5 Volt PCI slot has not crashed?
• What could be expected to happen in a future? Strange network behaviors as long as Quad RJ45 circuitry gets melted? Damages to the full system (motherboard, RAM, CPU... etc)? Or... is it possible that nothing will happen?

The motherboard is an HP P5LP-LE (Leonite).

EDIT: I have access to this sort of "network overclocked" machine, and I think I can perform any test that would be needed, like intensive LAN traffic, replace LAN cards to compare, or obtaining info with any program. It runs Windows XP and Ubuntu Linux Server v14.04 LTS. During the nights (when there will be nobody in the offices) I could probably even install some more operating system.

EDIT-2: Here is the detail of the cut. It seems clear to me that it is handmade:

and the rear side:

Can I have too high a PSU power rating?

I have just ordered a 650 W PSU for my computer which previously had a 300 W, in order to install a more powerful graphics card. However, I didn't check whether anything would blow up because it was too high - could there be any issues?

Also, what would I need to check to ensure the PSU would be compatible with all the other components?

Hooking up my power switch/reset switch/LEDs

I'm working on building a computer (first time for me). There are several plugs that I need to connect to the motherboard (Power LED, reset switch, etc). Of the two wires, they are either:

1. Color and white (reset switch, power LED, HDD LED)
2. red and black (speaker, power switch)

The manual for the motherboard has a nice diagram of where to plug them in, but has them labeled + or -. Which colors are positive, and which are negative?

Got shocked by a native dell laptop charger outputting 19.5 V 6.5 A DC. It was REALLY uncomfortable, but was that dangerous?

Okay.

My laptop was running out of battery. I grabbed my charger (outputting 19.5 V 6.5 A DC) which was plugged into the wall, and as I touched the end of the charger I got some electric shock going through my body to my other hand which was resting on the PC.

And I'm basically freaking out now. It felt far from good, but honestly I don't know if it is placebo (I'm kind of scared of electrical shocks).

So... How dangerous was this?

How does Windows detect battery issues?

I have a laptop that's a little over 5 years old, and I've never changed the battery, so I believe Windows 7 when it tells me "there is a problem with your battery", and to consider replacing it.

My question is: how does it detect a dodgy battery? Does the battery not have the same voltage that it used to?

Is it better to use an offset or manually set CPU voltage (with respect to CPU longevitity)?

The Background:

I recently built a new computer, and I'm working with the ASUS P8Z68-V Pro motherboard and Intel i7 2600k processor. While this question does not pertain specifically to my hardware, I mention what I have to explain the voltages/temperatures I get. Do note that the information in your answers should not pertain to my specific case, but computer hardware in general. Furthermore, the information should apply regardless of if the system is under-clocked, stock-clocked, and over-clocked.

The Details:

In my motherboard, there are two options that pertain to my question. The first is load-line calibration (LLC), and the second is setting the CPU voltage by manual/offset mode. After some experimenting with my manually set multiplier, I have come up with the following as a stable set of voltages in each voltage mode:

• Manual Voltage - 1.19V at idle , drops to 1.18V under load (LLC on high).
• Offset Voltage - 0.93V at idle, 1.19V under load, voltage spikes to 1.25V under load transitions (LLC is off).

Now I understand why the voltages result from each setting (like V_droop), and why I need to turn LLC on/off in each case, but there are two sides to the hypothetical coin here. While my load temperatures are about equal in each case, the CPU idles a few degrees cooler in offset voltage mode (due to the lower idle voltage).

That being said, in offset mode, I noticed an interesting side effect - load transitioning causes the voltage to spike up to 1.25V. I also noticed that the voltage stays at 1.25V when starting the computer (until Windows is fully loaded and SpeedStep begins to work... brownie points if you can also tell me why this happens). With LLC enabled on any setting in offset mode, the load and idle voltages remain the same, but the peak transition voltage gets a lot higher (over 1.3V).

Conversely, when I set the voltage to manual mode (with LLC enabled, since without it V_droop causes it to be unstable at idle), the CPU is constantly at ~1.17-1.18V, in both idle/load/startup. My point is that I don't see any voltage spikes between load transitioning - the voltage is almost constant, all the time.

Again, note that in both cases, my load temperatures are the same (a perfectly acceptable 65°C under a stress test, mid to high 50's under normal full load). Thus, I am not worried about temperatures (even at idle), but rather the longevity of the CPU with respect to these voltage settings.

The Question:

For the long-term use and stability of a computer, with respect to CPU degradation and longevity, is it better to use an offset voltage (which results in a lower idle but higher transition voltage) or manual voltage (roughly constant voltage)? Will the offset voltage spikes (although within my manufacturer's specified voltages) harm the CPU or cause it to degrade faster over time?

Assume the system is under load 60% of the time it is on (which is why I want to use offset mode - cooler and less power at idle).

Reason for bounty: I would appreciate some hard evidence (datasheets, research papers, studies, or any proof really) in favour of one method or another, specifically pertaining to fluctuating versus constant voltage.

Under what conditions will a group-regulated PSU damage a modern computer?

These days, group-regulated power supply design is considered obsolete and is ideally avoided—primarily due to the poor regulation under crossload. For example, Shilka pulls no punches here, and while OklahomaWolf is more subdued in this review it's hardly complimentary. Others around the place are positively rabid regarding group regulated PSUs.

Yet, I imagine there are hundreds of thousands (millions?) of users with group regulated PSUs that probably don't know there's a potential problem. Seasonic S12/M12, Antec Neo Eco/HCG, FSP Raider, etc., having been popular models.

So the questions:

1. Under what conditions will a modern general use or gaming PC cause a PSU to be crossloaded?

2. What is the practical risk of using a group regulated PSU under these conditions? As in, given the likelihood of it occurring combined with the likely effects, what problems are actually seen?

Are there examples of actual damage or instability caused specifically by a group regulated PSU's poor regulation?

(For the sake of this question, please assume the PSU is otherwise perfectly good quality—not a $2 doorstop—and it is specifically the group-regulated design in question).

What are good values for PSU voltages?

I have an odd computer I'm trying to fix that will crash only during the setup of an OS(crashes on every OS I've tried so far) It's not overheating and it is stripped down as much as possible and I've tried multiple harddrives, and memtest86+ can run on it for 3 hours without a crash or fail.

So, I was a bit stumped and was looking in the BIOS for possible causes and found a hardware monitor that shows PSU voltages. They are:

VCORE:  1.432V
3.3V:   3.136V
5V:     5.273
12V:    12.144V

I thought the 3.3V looked a little low, but I'm not really sure on how "bad" that is.

So, what are the good ranges for the voltages on each CPU rail?

How to optimize PLL voltage

I am overclocking my Core i7 (Ivy Bridge 3770K), aiming for a moderate overclock.
Currently I have it easily stable at a pleasant 4.4GHZ - BCLK defaulted at 100.00MHz, with the multiplier set to x44.

While it is currently stable (tested using Prime95 torture test for a few hours), it does generate some more heat than I would optimally like. Nowhere near overheating, but still requiring the fan to run a bit loud.

I read in this article on Overclock.net, and verified with more experienced overclockers, that lowering the PLL voltage in the UEFI should lower the temperature a little bit.

So, how much should I try to lower it? Just keep going iteratively, as long as it is still stable, or stop arbitrarily at 1.500v (as that article indicates)?
How much could I typically expect to lower the temperature? So far it seems I might have lowered it 2-3C, but its hard to tell since that is less than the fluctuations in ambient temperature.
Most importantly, What exactly does the PLL voltage setting even do? I would feel a lot more comfortable managing this setting manually, if I understood its function. I haven't found anywhere a better explanation of it's responsibilities in the system, other than explaining what a PLL is.

(My motherboard is a GA-Z77-D3H, if it matters...)

Is it safe to use a laptop AC adapter with 220V power if the AC cable is not rated for 220V?

The AC adapter supplied with my laptop is designed to accept voltage in the range of 100-240VAC at 50-60Hz, but the AC cable that plugs into the adapter unit itself is only rated to 125VAC 7.5A 2.5A. I know the adapter can accept 220V power, but is it safe to use this cable with the AC adapter to plug into a 220V socket?

Edit: The part in question is a 90W HP Smart AC Adapter. The laptop does not cause the AC adapter to draw more than about 80 watts from the socket (as measured with a Kill A Watt meter).

Edit 2: The amperage rating of the cable as marked on the attached label is 2.5A, not 7.5A.

CPUs: more transistors, less voltage?

I have read in an article that newer CPU cores have narrower circuit tracks so more transistors can fit in the core. The author wrote that since there are more transistors, the voltage is reduced.

"As the track width is reduced, more transistors can be placed within the same area, and hence the voltage can be reduced."

How come newer processors tend to be consuming less power when in fact, the number of transistors they hold doubles each year as suggested by Moore's Law?

Are all DDR3L (1.35V) DIMMS safe to use in a computer system that uses DDR3 (1.5V) DIMMs?

The sales support of (the consumer/prosumer sales subsidiary of) a DRAM manufacturer answered a pre-sales question I made with (translated from an email in French):

1.35V Memory DIMMs are dual voltage, and can work at both 1.35V et 1.5V; your computer system will adjust the voltage automatically as required by the motherboard and other factors like pre-existing DIMMs kept in the computer.

I was initially skeptical, but indeed the data sheet of even some relatively old DDR3L SDRAM chip states their are

Backward-compatible to VDD = VDDQ = 1.5V ±0.075V

and

Refer to the DDR3 (1.5V) SDRAM data sheet specifications when running in 1.5V compatible mode.

I this the case for all DDR3L (1.35V) DIMMS on the market? If not, it is because they are unspecified, or without proper SPD memory content, or otherwise inoperative, or perhaps plain destroyed, when operated at 1.5V?

Note: This is an engineering question; I'm looking for technical details explaining incompatibility, if any. Like that pure speculation: for cost reason, some DDR3L chips are not tested at 1.5V (or happened to fail that test), and are thus sold on DDR3L 1.35V-only DIMMs not indicated as 1.5V-compatible in the SPD memory.

Can computer power supplies use North American 240V (hot-hot-ground)?

Simple question: Most computer power supplies are auto-sensing between 110V/120V and 220V/240V. This begs the question, can they use 240V in North America i.e. connected to both hots (red and black)?

How do I change GPU core voltage?

I've got an AMD Radeon 6790 with Mint 14, and I'm experimenting with over-clocking the GPU for Bitcoin mining. Right now, I'm running it at 990/130 stable at stock voltage (I think 1.185V), but I think I could run at a higher core clock if I increase the voltage. The only problem is I can't find a way to do it.

AMDOverdriveCtrl allows me to change the voltage within a range, but not beyond stock voltage ranges.

Can someone please tell me how to set the voltage on my GPU? I'm willing to try third-party software if necessary.