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Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

xbitlabs.com

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Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#11

Post by astrodust »

I'm still perplexed why Intel doesn't redesign their CPU socket to be more efficient at delivering power. They're channelling a lot of juice through some very tiny pins or pads, a fairly straight-up evolution of the old 8088 chip that fit into a DIP socket.

Is it somehow not practical to have several bigger pins for power that can handle more current than to have literally hundreds of pins dedicated to power? A surprising percentage of the pins on a modern Intel chip do nothing more than power the chip. The traditional pair of +Vcc and GND pins just can't cut it, apparently, and no wonder with some chips drawing over 100W of power.

Not too long ago video cards started taking a direct feed from the PSU rather than relying on the PCI or PCIe bus. It's surprising the same thing hasn't happened to high-power integrated circuits.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#12

Post by criley »

dman wrote: post #8
twoodfin wrote: post #5

Only if you want the C6/C7 states, which are the really low power draw ones. If you're the kind of person who builds your own PC, it's unlikely you really care about saving a few watts while in sleep. At worst, you'll get Ivy Bridge-level power consumption.

On the contrary in 2013 the kind of person who builds their own PC's is the only one who likely cares about technical specs. If "good enough" is good enough for you there is very little reason to build your own box these days.

On the contrary to your contrary: the kind of person who builds their PC is the kind who customizes how it works when they're using it. There's no automatic assumption that they also harbor green feelings and want lower power consumption for idle/sleep.

Hell, many are proud of their beefy 1kW+ power supplies and the ridiculous power load they draw.

Others are proud of their energy-destroying bit-coin mining setups.

You certainly can't assume that the home builder cares at all about power consumption.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#14

Post by akiselev »

astrodust wrote: post #11

I'm still perplexed why Intel doesn't redesign their CPU socket to be more efficient at delivering power. They're channelling a lot of juice through some very tiny pins or pads, a fairly straight-up evolution of the old 8088 chip that fit into a DIP socket. Is it somehow not practical to have several bigger pins for power that can handle more current than to have literally hundreds of pins dedicated to power? A surpr…

The vast majority of power efficiency losses are in the copper interconnects within the chip, not the copper pins.

Oh also, if you want fewer power pins, get ready for more heat and way more expensive CPUs. The pins are placed to be as cost effective and efficient as possible to power the individual chip modules (many of which will operate at different voltages). Also, it's way cheaper to convert power on the motherboard than within an already incredibly constrained CPU package.

Edit: "vast majority" as far as power and other connections to the board go, the transistors create way more heat than the interconnects.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#15

Post by wtallis »

Just how much of the system is getting shut off in these new C-states? A lot of the best power supplies have a single 12V rail, and the 3.3V and 5V rails are provided by stepping down the voltage from the 12V rail. It seems like any PSU with that kind of design wouldn't be affected unless the total system power consumption drops below 6W, which would require shutting off at least the expansion cards, disk drives, any power-hungry USB devices, and potentially the case fans. Even 4 DIMMs plus the keyboard and mouse necessary to wake up the system might be sufficient to keep the power draw high enough.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#16

Post by dman »

criley wrote: post #12
dman wrote: post #8

Earlier quoted context omitted.

On the contrary in 2013 the kind of person who builds their own PC's is the only one who likely cares about technical specs. If "good enough" is good enough for you there is very little reason to build your own box these days.

On the contrary to your contrary: the kind of person who builds their PC is the kind who customizes how it works when they're using it . There's no automatic assumption that they also harbor green feelings and want lower power consumption for idle/sleep. Hell, many are proud of their beefy 1kW+ power supplies and the ridiculous power load they draw. Others are proud of their energy-destroying bit-coin mining setups.…

Fair enough. On the other hand segments of the market who think of the computer as a blackbox that is a bicycle for the mind are even less likely to care about any individual specification. Most people I know who build their own PC's are trying to optimize for some spec that manufacturers dont usually care about - loudness, gpu performance, low power draw, size, aesthetics.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#17

Post by hga »

dman wrote: post #8
twoodfin wrote: post #5

Only if you want the C6/C7 states, which are the really low power draw ones. If you're the kind of person who builds your own PC, it's unlikely you really care about saving a few watts while in sleep. At worst, you'll get Ivy Bridge-level power consumption.

On the contrary in 2013 the kind of person who builds their own PC's is the only one who likely cares about technical specs. If "good enough" is good enough for you there is very little reason to build your own box these days.

How about the MTBF spec?

I exclusively use server or workstation/server class motherboards from Supermicro or Tyan not just for myself but also for my parents, so I can then largely ignore the hardware for 5+ years plus not worry about non-reproducible errors from radiation flipping a DRAM bit. I've done this since 1995-6 and never had one fail in the field except through an act of God (http://en.wikipedia.org/wiki/2011_Joplin_tornado).

For this purpose, decreasing stress from thermal cycling is good.

(Yeah, they're grossly overpowered for what my parents do, but since I'm not including my labor in the cost they really don't cost that much.)

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#18

Post by ajross »

FTA, quoting Robert Pearce: "I fully expect the [motherboard] companies to disable C6/C7 in the BIOS (though consumers could enable it if they chose to) as there are simply too many PSU's in the market space which might not work correctly."

... because the motherboard manufacturers can't figure out how to stuff a 240 ohm resistor across the 12v rail?

Edit to be fair: if the power savings from going from the legacy suspend to the Haswell states is less than 600mW, then this isn't worth it and disabling the Haswell states is the right solution. In my experience though, PC motherboards almost never idle at less than 3-5W.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#19

Post by nilsimsa »

astrodust wrote: post #11

I'm still perplexed why Intel doesn't redesign their CPU socket to be more efficient at delivering power. They're channelling a lot of juice through some very tiny pins or pads, a fairly straight-up evolution of the old 8088 chip that fit into a DIP socket. Is it somehow not practical to have several bigger pins for power that can handle more current than to have literally hundreds of pins dedicated to power? A surpr…

Chips have multiple power pins for signal integrity issues. You want the power source close to where it is being used, particularly for IO pads. Even chips with low power requirements will have multiple power pins.

Re: Intel Core i “Haswell” CPUs May Require New Power Supply Units for PCs

#20

Post by EvilLook »

hga wrote: post #17
dman wrote: post #8

Earlier quoted context omitted.

On the contrary in 2013 the kind of person who builds their own PC's is the only one who likely cares about technical specs. If "good enough" is good enough for you there is very little reason to build your own box these days.

How about the MTBF spec? I exclusively use server or workstation/server class motherboards from Supermicro or Tyan not just for myself but also for my parents, so I can then largely ignore the hardware for 5+ years plus not worry about non-reproducible errors from radiation flipping a DRAM bit. I've done this since 1995-6 and never had one fail in the field except through an act of God ( http://en.wikipedia.org/wiki/…

I consider it borderline negligent to use anything other than ECC RAM in any machine where you care about not corrupting your data with a flipped DRAM bit.
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