Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

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phositadc
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Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by phositadc » Sun Mar 30, 2014 12:35 pm

Planning to build a new rig in an Antec ISK-110 mini-ITX case, which has a 90W PSU (I may get a 150W PicoPSU, but would prefer not to). I've seen success stories from people using 65W CPUs with the case, so I was thinking about getting an i5-4670S (max TDP of 65W) or even an i5-4670T (even lower max TDP).

But I've seen lots of posts where people say you are better off just getting the "K" version of the CPU and undervolting and/or underclocking it yourself.

How easy is it to achieve the power profile of an i5-4670S by simply undervolting and underclocking a 4670K? Is it a virtual certainty that a 4670K would be able to get to that power profile, or would some 4670K silicon not be capable of handling the undervolt and remaining stable?

Also, how exactly do you achieve the undervolt? Would you do a voltage offset of like -0.1v in the BIOS, so that all voltages run at 0.1v less than auto? Or is there some other preferred method? Any advice appreciated.

quest_for_silence
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Re: Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by quest_for_silence » Mon Mar 31, 2014 9:56 am

phositadc wrote:Also, how exactly do you achieve the undervolt? Would you do a voltage offset of like -0.1v in the BIOS, so that all voltages run at 0.1v less than auto? Or is there some other preferred method? Any advice appreciated.


AFAIK you don't need a -K SKU to undervolt it, but you do need a motherboard which allow a negative offset to Vcore (as the ASUS usually do, but it's just an example).

The BIOS (UEFI) method is more trouble-proof than any sw-based method, at least under Windows (like the old RM Clock), so I would go for it.

About the various quoted CPUs, providing you won't overclock, I would pick the cheapest I could find.

phositadc
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Re: Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by phositadc » Mon Mar 31, 2014 3:27 pm

quest_for_silence wrote:
phositadc wrote:Also, how exactly do you achieve the undervolt? Would you do a voltage offset of like -0.1v in the BIOS, so that all voltages run at 0.1v less than auto? Or is there some other preferred method? Any advice appreciated.


AFAIK you don't need a -K SKU to undervolt it, but you do need a motherboard which allow a negative offset to Vcore (as the ASUS usually do, but it's just an example).

The BIOS (UEFI) method is more trouble-proof than any sw-based method, at least under Windows (like the old RM Clock), so I would go for it.

About the various quoted CPUs, providing you won't overclock, I would pick the cheapest I could find.
Thanks for the info. Just to be sure I understand, you are saying that I could undervolt an i5-4670 just as easily as I could undervolt an i5-4670K?

That would be good news, as I definitely do not intend to over clock. Though, I assume I would need the K in order to underclock?

Vicotnik
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Re: Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by Vicotnik » Tue Apr 01, 2014 4:50 am

K means unlocked multiplier and nothing more as far as I know. On both K and non-K the multiplier can be lowered (edit: T, S etc, same thing) and any voltage adjustments depends on the motherboard.

kater
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Re: Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by kater » Tue Apr 01, 2014 6:10 am

You don't really need to go for the K. E.g. with 2500K, the chip had (apart from unlocked upwards multiplier) a slightly stronger graphics chip. So maybe 4670K also has beefier graphics. But that's not really a point to buy it :) For your needs, I'd suggest picking a regular, non-K chip (if only to save a few bucks).

My I5 2400 nicely undervolted on a regular, budget GB P67 board. I now have Z77X-D3H, so also a regular mobo, and it also sports undervolting options. So far I was able to deduct 0.2V from def Vcore. Perhaps ii'll go even lower, I don't know, got no time to play with it now.

phositadc
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Re: Buy i5-4670S (or 4670T) or buy i5-4670K and undervolt?

Post by phositadc » Tue Apr 01, 2014 7:44 am

Thanks for all the replies. The discussion has been helpful.

P.S. Does anybody know if the Gigabyte H87N supports undervolting via voltage offset? I understand that only the Z87 chipset supports overclocking. The Gigabyte manual does not appear to be helpful because it is a combined manual for both the Z87 and the H87.

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