Windows 7: RAM questions

Hi all,

I have 4 x 2Mb Patriot DDR3 1600MHz in the correct slots according the the manual in my P6T mobo.

I have two queries regarding RAM I hope you can help with.



1/ I have read somewhere that i7920 CPU's operate better with a "triple channel" setup with only three slots filled. Would I get better performance if I take one RAM module out and have 6MB?

2/ While reading the mobo manual I notice it is recommended that only RAM with voltages of less than 1.65 be installed or possibly risk CPU damage. On checking the compatibility chart I found that the Patriot RAM i have is rated at 2.0 volts. Could this cause problems and/or should I buy new RAM?

Thanks,
Harry

I have a P6T Deluxe (v. 1).

1) I'd think so. However, dual channel is a supported configuration. I don't know how much real-word performance gain you might acheive by going to triple channel.

2) What voltage is actually being applied to the DIMMs? I always set mine manually in the BIOS settings. (I doubt that you're getting 2.0V. The RAM may run well at a lower voltage, but maybe not at DDR3 1600.)

My approach to triple channel was to go the other way: I have six DIMMs. I run them at DDR3 1600, but I had to back the timings off to 9-9-9-24 (rather than the nominal 8-8-8-24) to get stable performance at 1.65V.

I'd agree with Bob.

There is a marginal improvement in some sense in triple channel mode.

HOWEVER, if you ever need that 7th and 8th gig of RAM, if it's not in the slot, you can't use it. So--if you know your usage is always 6 and under, you should see very slight improvements in some uses by pulling a stick out. But you may never notice the difference.

If you DO need that 7th and 8th gig, even rarely, you will likely apprecite those 2 gigs much more than you would appreciate triple channel rather than dual channel.

If you have no intention of overclocking, you went way overboard unnecessarily on RAM speed and the fact that it is 1600 won't help. The 1600 would run at the 1066 default.

The normal way to buy RAM on a triple channel board is to buy in units of 3, but it will use all 4 if 4 are installed. But I think 4 sticks rather than 3 would force you back to dual channel.

1600 speed RAM capable of that voltage is typically sold to a hard-core overclocker who is willing to endure system crashes and high temperatures with the goal of pushing the CPU to the highest possible speed. Otherwise it is wasted money though it may work well without overclocking.

Thanks guys for your help. I'll leave it alone, it's working OK but I think I should have researched a little more before buying the comp parts. Oh well, it was my first build so lesson learned

As an afterthought, I checked with CPU-Z and this attached screen (SPD) baffles me:
Does that mean anything to you?

Here is approximately what it means; I am not expert.

The rows from CAS latency through TRC are "timings" for each of the mHz settings (457, 533, and 800). Lower timing numbers are "better".

Non-overclocked in this case would mean RAM running at 533mHz, with the timings and voltages shown in the 533 column. Note that this runs the RAM at 1.500 volts

Max RAM overclock would be RAM running at 1600 mHz, with the times and voltages shown in the 1600 column. Note that this runs the RAM at 1.900 volts.


It appear this particular RAM can be under-clocked to 457 mHz. Notice it gives a little bit "tighter" timings.

Note that the max overclock 1600 column means the timings are a bit worse ("looser"). Ideally, you'd prefer not to have to accept looser timing, but you have to accept it if you want the RAM to run at the faster 1600 speed.

Higher voltage implies heat, wear and tear, and crashing (sooner or later)

In a motherboard with lots of features, you can manually adjust voltage. In others (like my Intel board), you can't adjust it. That's why an over-clocker would not be caught dead with an Intel brand board.

However, some recent Intel processors have a "Turbo' capability that causes 1 core (out of 2 or more) to run at 20% or so above stock speed without buying heavy duty RAM and fiddling in the BIOS. Very desirable if the work you are doing only utilizes a single core anyway.

The SPD (serial presence detect) is a ROM chip included with DIMMs that defines the voltages, timings, and frequencies it is specified to operate at.

I'm not expert at that. It says, for example, that you need 1.9V to run at DDR3 1600 (800 MHz actual, double data rate). At 1.5V, you can get DDR3 1066. I wonder what would work at 1.65V?

This sort of DDR3 may not be ideal for a P6T, if you really want DDR3 1600 performance.

Txs again guys,

Not being a tech-head, I'm more confused than ever . I have no intention of overclocking so I'm leaning towards perhaps replacing the RAM with a more suitable configuration. I think my i7920 restricts RAM to 1066Mhz in standard form anyway. Should I get 3 sticks x RAM of 2Gb, 3Gb or 4 Gb each? Maybe lower than 1600Mhz?
Harry

Now you have me confused.

Why would you even consider replacing your RAM??

Consider this analogy:

You need to store 10 gallons of water. No more and no less.

Your choices:

A 12 gallon glass container purchased at Walmart for $9.99.

A 20 gallon Steuben Crystal decanter purchased at Tiffany for multi-thousands of dollars.

Both do exactly what you want to do. You choose the latter.


Why would you change? The Steuben glass is overkill from a practical standpoint, but it is a sunk cost, irretrievable unless you have a known buyer ready to bail you out for 100 cents on the dollar.

Is the Patriot RAM defective? What doesn't it do that you wish it did do? How is your PC suffering because of the Patriot RAM?

It may be that you can find some other RAM that has slightly tighter timings than the current Patriot RAM. The chances of you ever being able to detect the difference without a benchmark are effectively zero.

If you enjoy fiddling, have an obsessive nature, and have money falling out of your pockets, go ahead on with it--but I see no practical value at all.

If you have a valid reason to need more RAM as opposed to different RAM, that's another story entirely--but how have you established that? Even if you need more RAM, I certainly would not throw out 8 gigs of Patriot 1600 so I could install 12 or 16 gigs of 1066.

Point/s taken I reckon you are right.......why bother??? It's working OK as is, best left alone. Thanks mate

Not to play Devil's advocate, but the Patriot memory requires 1.9V to run at DDR3 1600. 1.9V shouldn't be used on a Core I7 motherboard. (1.65 is the maximum.)

It will clearly run at usable frequencies at lower voltages, but if our antipodean chum wants DDR3 1600...

Actually, it may be possible to use RAM that requires a higher voltage:

bit-tech.net | Guide - Overclocking Intel's Core i7 920

According to this, if the RAM voltage is within 0.5V of the "uncore" voltage, the Core I7 CPU's memory controller will be safe. Anyone care to try 1.9V?