65w: i7-4790s vs i7-4790 underclocked

[jrgreed]

I am working on a silent PC right now, and as part of the set-up I am looking for the most powerful 65w processor I can get, to work with passive cooling.

I have read in a couple different places that the I7 4790/S/K models have no manufacturing difference, and that its simply that the more reliable chips get a K rating while the less reliable chips only capable of running at lower power get S ratings... How true is this?

Mainly, I am wondering if I would be better off getting a regular I7-4790, as opposed to an I7-4790S, and underclocking it to be 65w (it would be my frirst attempt at modifying stock settings fyi ).

Is that even possible? Is the 4790 a more reliable chip then a 4790S in any way? Or would I be wasting my time? (Note: I have no intentions of going above 65W for performance reasons, fan-less cooling is important in this build)

Lastly, I am assuming that the 65w i7 Haswell build is my best bet for Power/Heat ratio, but feel free to chime in with any suggestions

 

[faalin]

you cant overclock or downclock a 4790/s the multipliers are locked on those cpu's, the only thing you can change on them is the block and I would highly recommend not changing that at all.

You can downclock the 4790K as the multiplier is unlocked but I don't understand why you would pay that much for a cpu and then handicap it.

 

[dish_moose]

The 4790k will only heat up when you push it - normal things like watching movies or web surfing only get the cpu to 35C with a decent cooler. If you underclock it I'm sure it would be a power miser. Make sure you get a decent quiet cpu cooler.
-Bruce

 

[jrgreed]

you cant overclock or downclock a 4790/s the multipliers are locked on those cpu's, the only thing you can change on them is the block and I would highly recommend not changing that at all.

You can downclock the 4790K as the multiplier is unlocked but I don't understand why you would pay that much for a cpu and then handicap it.

I want to go with a fanless cooler to go silent. In addition, I want to go with a fanless case, so that fanless CPU cooler will be put to the test... The PC wont be for me and the person wont be computer savy, so I dont want to give them something prone to overheating as they would be confused trying to do something as simple as plugging in a case fan...

I dont want to put a fanless CPU cooler billed for a max of 95w into a fanless case with an 88w i7 that will be used for long periods to do processor-intensive tasks.... At the same time, I need the most powerful processor I can get to run CPU-intensive tasks, but at 65w or less...

If you have a better, more powerful, low-power/heat solution suggestion, I am all ears

 

[jrgreed]

The 4790k will only heat up when you push it - normal things like watching movies or web surfing only get the cpu to 35C with a decent cooler. If you underclock it I'm sure it would be a power miser. Make sure you get a decent quiet cpu cooler.
-Bruce

No fan on cooler, so it will be pushed. I wants a 100% silent design.

'power miser'? does that mean it will still draw the power but not use it?

At the end of the day the question is, would an underclocked 4790k be able to run as cool as a 4790s if underclocked? This is specifically for CPU-intensive tasks, so I need to have a power cap it cant exceed.

 

[dish_moose]

Fanless options require convection for cooling - with no fans at all you are looking for trouble. Even fanless require air to move.
-Bruce

 

[jrgreed]

Fanless options require convection for cooling - with no fans at all you are looking for trouble. Even fanless require air to move.
-Bruce

Inverted motherboard/case to allow to maximum heat dispersion through the top of the case, as well as avoiding stacking components that produce heat (CPU, GPU, PSU)... I've seen fanless designs done with far-less heat ventilation then I intend, so I am hoping I will be fine.

I am considering a single fan at the bottom (and closing of other vents to direct the air-flow) in order to combine a slight intake with the expanding heat and create some outward flow through the top of the case. Still, I would really like to see if it is possible to run a setup with no fans at all, as that is ideal. I will ofcourse give it some stress testing after the build to find out...

That said... i7-4790k vs 4790s...

can the i7-4790k be downclocked to run as cool as a i7-4790s? Are the i7-4790s' inferior in any way?

 

[dish_moose]

They can be down clocked lower than the 4790S. When I'm watching movies with firefox with 5 tabs open my cpu clock is at 800Mhz. ;-) You can set your max clock to whatever you want.
-Bruce