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Linked means that the speed of the memory bus increases at the same rate as the front side bus. Some motherboards allow you to overclock the memory and CPU to different ratios (ex: 5:4) or completely independently.

Synced means the memory bus and front side bus are both running at the same clock speed.

1:1 also means the memory bus and the front side bus are running at the same speed.

Front side bus on an Intel = FSB/4 since it is "quad pumped". For example, a Q6600 bone stock with its 1066 advertised fsb is actually running 266MHz.

DDR2 memory is always rated at its "effective" speed as welll; not unlike Intel's "quad pumped". Since it can do 2 operations-per-clock, it's advertised at double the speed the memory bus is actually running at. So DDR2 800 is really running at 400Mhz.

If we wanted to link and sync the Q6600 in my example to the memory in my example, we'd have to increase the front side bus to 1600 (400*4) or lower the memory to 533Mhz.

Example 1:
Q6600 @ 1600 or FSB400*4
Memory DDR2 800 (400*2)

Example 2:
Q6600 @ 1066 or FSB266*4
Memory DDR2 533 (266*2)

Some have better luck keeping it linked and synced. I personally do.
 

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The 1:1 ratio myth is all hype, you do not get any better performance just by having your FSB and your memory at the same speed. Although, it is useful to be able to use unlinked mode because your memory speed isn't dependent on how your CPU is clocked. If you cannot use/don't have unlinked mode (most people don't have the option), then overclock your CPU as much as possible (within comfort) and after that, set your RAM at the fastest stable speed
.
 

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Quote:


Originally Posted by Duckydude
View Post

The 1:1 ratio myth is all hype, you do not get any better performance just by having your FSB and your memory at the same speed. Although, it is useful to be able to use unlinked mode because your memory speed isn't dependent on how your CPU is clocked. If you cannot use/don't have unlinked mode (most people don't have the option), then overclock your CPU as much as possible (within comfort) and after that, set your RAM at the fastest stable speed
.

not 100% true with nvidia chipsets once you get around a 460fsb a 1:1 becomes almost 100% necessary if you wanna push farther.
 

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Iconoclast
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NVIDIA chipsets can also see a modest performance advantage at 1:1, as they can skip certain parts of the clock crossing procedure. Intel chipsets do the same kind of clock crossing regardless of ratio, so for best memory performance, the highest ratio you can stably use at a given FSB speed will be the best.
 

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Good info....

Related question:

I'm building a gaming rig (first time for me) with the following components:

EVGA NForce 790i Ultra MB
Intel Q9550 (1333mhz) Quad
Patriot Viper DDR3 1600mhz (4g - 2x2)

I intend to run the memory at it's rated 1600mhz.
In order to link and sync, how do I proceed?

Also, if I may, an unrelated question....when overclocking the cpu, how do I know what voltage to set as the speed is increased? Is this done manually?
I'm hoping to increase from the stock 2.83ghz to 3.4-3.6ghz., which I think is safely below what others have done.

All help is greatly appreciated since I'm learning as I go here.
Also, please advise if I should post any of this in a new thread.
 

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Iconoclast
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You do not want to run a 1:1 ratio with a DDR3 mobo, even an NVIDIA one. The 790i/DDR3 combo is geared for a 2:1 ratio, offering similar benefits to a 1:1 ratio on the 680i and 780i chipsets (i.e. the ability to skip parts of the clock crossing procedure, effectively running a lower tRD).

In order to run linked at a 2:1 ratio, with your memory at it's rated speed, you will need to set your FSB to 400MHz (and obviously select the linked option along with the 2:1 ratio).

As for your questions regarding voltage: Yes, it's best done manually, and you know by trial and error. Set a voltage that seems reasonable for a give clock speed and do some serious stress testing. If the tests reveal no problems, lower voltage and do it again. If the tests reveal problems, raise voltage and do it again.

Ideally, you want to be using the lowest possible voltages that leave you with a 100% stable system.
 

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Thanks for the tips.
Now that I have my system powered up, and the OS installed (64bit), I'd like to set my FSB to 1600mhz to match the rated speed of the ram. Would I then just set the FSB to 400mhz, with no need to adjust the cpu voltage? I'm manually setting the ram to it's rated 7-7-7-20 1600mhz.
Thanks again for the help...
 

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You should be able to run the q9550 at that speed on stock voltages. If it's not prime stable and youre sure your ram is increase vcore a bit. It shouldnt take much to run stable at 3.4.
 

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Looking through the bios, it looks like I set the FSB in actual mhz. Would you happen to know if I should link and sync, or just set unlinked.....increase FSB to 1600mhz, and manually set rated speed and voltage for the ram?
Ram is rated at 7-7-7-20 1.9v 1600mhz.
I'm posting my current default bios settings below.
Not sure what spread spectrum is, but it seems most people with these boards disable all of this.

Thanks again...

BIOS Version: P07
**System **
CPU Freq, MHz: 2833.3 GHZ
FSB Reference Clock, MHz: 1333.3
CPU Multiplier: [8.5]
PCle x16-1 & 16-2, MHz: [100]
PCle x16-3, MHz: [100]
SPPc->MCP Ref Clock, MHz: [200]
nForce SPP --> nForce MCP: [5X]
nForce SPP c-- nForce MCP: [5X]
**Spread Spectrum**
CPU Spread Spectrum: [Center Spread]
HT Spread Spectrum: [Auto]
PCle Spread Spectrurn(SPP): [Disabled]
PCle Spread Spectrurn(MCP): [Auto]
SATA Spread Spectrum: [Disabled]
**FSB & Memorv Config**
FSB - Memory Clock Mode: [Auto]
FSB - Memory Ratio:
FSB (QDR), MHz: Auto [1333.3]
Actual FSB (QDR), MHz:1333.3
x MEM (DDR), Auto MHz: 1066.7
Actual MEM (DDR), MHz: 1066.7
P1: [AUTO]
P2: [AUTO]
**Memory Timing Setting**
Memory Timing Setting: [manual]
tCL (CAS Latency): 7
tRCD: 7
tRP: 7
tRAS: 20
Command Per Clock: [1T]
** Advanced Memory Settings **
tRRD: [Auto]
tRC: [Auto]
tWR: [Auto]
tWTR: [Auto]
tFAW: [Auto]
tREF: [Auto]
**System Voltages**
CPU Core: [1.19v]
CPU FSB: [1.1v]
Memory: [1.500v]
nForce SPP: [1.30v]
nForce MCP: [1.500v]
GTLVREF Lane 0: [Auto]
GTLVREF Lane 1: [Auto]
GTLVREF Lane 2: [Auto]
GTLVREF Lane 3: [Auto]
**CPU Configuration**
Limit CPUlD Maxval: Disabled
Intel Speedstep: Disabled
xPPM Mode: [Native]
CPU Thermal Control: [Disabled]
C1E Enhanced Halt State: [Enabled]
Execute Disable Bit: [Enabled]
Virtualization Technology: [Enabled]
CPU Core 0: [Enabled]
CPU Core 1: [Enabled]
CPU Core 2: [Enabled]
CPU Core 3: [Enabled]
 

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I have a quick question regarding this also. To clarify what linked or unlinked is, in my motherboard where I enter in fsb speed to overclock, do I set the ram speed from auto to a lower setting until it says 1:1 in cpu-z? i think default it sets it at around 800 mhz which is 2:3 I think. ? just asking a really specific question
 

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In my opinion go unlinked i was able to do some amazing things that way see for your self.

STOCK



Overclocked



and as far as the memory i had a pair of DDR3 1023Mhz STOCK and was able to bring them up to 1350 with no problem.
 
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