I thought Sandy Bridge Pentiums restricted RAM speed to 1066MHz?

[mikeymikec]

I've got a new computer build with a Pentium G620, and simply because the memory was the right price I ended up with 1600MHz DDR3. The BIOS and memtest86+ v4.2 are reporting the RAM speed as 1600MHz...

I'll try CPU-Z in Windows tomorrow, but I'm pretty sure I haven't seen this happen before.

 

[DaveSimmons]

No, it's that the faster speed just doesn't really help.

The advice was to not pay extra for faster RAM, especially since early on some of the 1600 DDR3 required running at a voltage that SB motherboards didn't like.

 

[Hubb1e]

I believe it's the Celerons that were limited to 1066. I bought 1600 too just in case I upgraded the processor and they are like a buck more.

 

[mikeymikec]

Ah, thought so:

http://ark.intel.com/products/53480/Intel-Pentium-Processor-G620-3M-Cache-2_60-GHz

Compared to say:

http://ark.intel.com/products/65693/Intel-Core-i3-3220-Processor-(3M-Cache-3_30-GHz)

(see 'memory types')

On previous builds with G620s, even though I'm using say 1333MHz memory, it gets limited to 1066MHz, and trying to set it manually in the BIOS just causes the next boot not to work and then the BIOS goes back to default settings. On this build (same board as previously), it auto-detected 1600MHz correctly and seems to be using it. Odd.

I know that the extra RAM speed doesn't help very much, I didn't go out of my way to buy faster RAM that I thought would run at 1066MHz I just found it odd, and wondered if anyone has any ideas why.

 

[mfenn]

1066 is the maximum "supported" speed on those chips. Any more than that and you're technically overclocking. That being said, there is no physical difference between the IMC of a i3 3200 and that of a G620, the only difference is the speed that they were tested at. So if you get a "good" chip, you can dial in 1600 no problem.

 

[mikeymikec]

So what you're saying is that they haven't been purposefully hobbled to only run the memory at 1066MHz.

 

[bononos]

So what you're saying is that they haven't been purposefully hobbled to only run the memory at 1066MHz.

At least some of them at least, some/most(?) are locked at 1066.

 

[VirtualLarry]

SB Celeron CPU is limited to DDR3-1066 RAM.

SB Pentium CPU is limited to DDR3-1333 RAM.

If you have one if those chips, and it is letting you run at 1600 RAM, then it is defective and should be RMAed.

Edit: After reading the prior links to Intel's site, it appears that I am wrong, and both SB Celeron as well as Pentium are crippled down to 1066 speeds.

 

[SPBHM]

SB Celeron CPU is limited to DDR3-1066 RAM.

SB Pentium CPU is limited to DDR3-1333 RAM.

If you have one if those chips, and it is letting you run at 1600 RAM, then it is defective and should be RMAed.

I'm pretty sure any Sandy Bridge can handle 1600+
and if the motherboard is not locking anything, any SB also should be able to have the IGP and IMC overclocked.

the Celeron might only be "validated" for 1066, but as I said, it's a sandy bridge CPU, so it should be fine with higher clocks, if it's possible to overclock.

 

[Charlie98]

So all that Trident X RAM I just put in my G620 HTPC is being wasted???

The 1333 RAM in my HTPC is running at 1066MHz (according to CPU-z.) I've not even looked to see if it's OC'able in the B75's BIOS... it's just an HTPC.

 

[mfenn]

So what you're saying is that they haven't been purposefully hobbled to only run the memory at 1066MHz.

Depends on how you look at it. No in the sense that there is no technical limitation or change that prevents them from running at 1600 MHz or higher. Yes in the sense, they aren't validated at any speed higher than 1066 MHz (or whatever) so a really marginal memory controller can slip through.

 

[VirtualLarry]

As far as I am aware, they are in fact intentionally crippled.

 

[mfenn]

As far as I am aware, they are in fact intentionally crippled.

Nope, you can set the DRAM speed to whatever you want as long as your mobo will let you. That being said, buying a Z77 board to use with a Celeron seems kind of dumb.

 

[piasabird]

Yes and no. Depends on the motherboard and the RAM. If the processor cant go that fast, what good will the faster RAM be? Some motherboards specifically say you have to have an Ivy Bridge processor to run RAM at that speed. Some motherboard may let you overclock the RAM, but that is a separate issue.

So will the processor just slow down the RAM anyway? If you can get it to work you could buy a better processor later.