can a cpu handle higher clock speeds in dual channel?

[Deminisher]

hey , i currently have an i5 2430m and while attempting to max it out (upgrade wise)
 a question popped up in my head.,, is it possible for my cpu which can handle upto 1333 max memory speed handle the same speed in dual channel?i was wondering because i currently want to buy two sticks of sodimm ram with speeds of 1600 mhz so ..... in dual channel it should be about 800 mhz so theoritically if i had 2666 sticks in dual channel will they run at my cpu's 1333 supported memory speed or is the supported speed of 1333 mhz only specify single channel and therefore i can have a max mem speed of 666.5,,, btw i know ddr3 doesnt have 2666 mhz sticks i was just wondering if i should pay more for a speed that i wont be able to make use of, thanks in advance!!

 

[da na]

In dual channel, your CPU will run both memory sticks at the speed of the ram, or the max supported speed of the processor. So no, dual channel doesn't change the clocks of the ram.

[Deminisher]

2 minutes ago, Mel0nMan said:

In dual channel, your CPU will run both memory sticks at the speed of the ram, or the max supported speed of the processor. So no, dual channel doesn't change the clocks of the ram.

so no speed benefit?

 

 

[Hairless Monkey Boy]

You seem to have a deep misunderstanding for how memory speed works. The simple answer to your question is that there is no difference between dual and single channel in terms of what the CPU supports.

1 minute ago, Deminisher said:

so no speed benefit?

Dual channel is faster than single channel by nearly double, but it does not operate at a different frequency.

[Hairless Monkey Boy]

Note the difference between DDR (Double Data Rate) and Dual Channel.

 

https://en.wikipedia.org/wiki/Double_data_rate

 

https://en.wikipedia.org/wiki/Multi-channel_memory_architecture

[Deminisher]

3 minutes ago, HairlessMonkeyBoy said:

Note the difference between DDR (Double Data Rate) and Dual Channel.

 

https://en.wikipedia.org/wiki/Double_data_rate

 

https://en.wikipedia.org/wiki/Multi-channel_memory_architecture

 

5 minutes ago, HairlessMonkeyBoy said:

You seem to have a deep misunderstanding for how memory speed works. The simple answer to your question is that there is no difference between dual and single channel in terms of what the CPU supports.

Dual channel is faster than single channel by nearly double, but it does not operate at a different frequency.

you know how in dual channel mode if you run memtest for example or cpuz (i think) it reports half your memory speed? that is what made me

think dual channel mode operates at a different frequency

, soooo just to make sure i understand correctly if i were to put two sticks  of 1600 mhz memtest,cpuz,etc.. will report what exactly? 1333 ÷ 2 or 1600 ÷2 (please excuse my ignorance lol)

 

[Kilrah]

7 minutes ago, Deminisher said:

you know how in dual channel mode if you run memtest for example or cpuz (i think) it reports half your memory speed?

That has nothing to do with dual channel

 

Memory frequency = 1333MHz (CPUz is correct)

Memory transfers per second = 2666MT/s because DDR, 2 transfers per clock

 

Dual channel = still 2666MT/s to each stick, just on 2 sticks simultaneously so double total bandwidth, but that doesn't show in any frequency/transfers per second number.

[Hairless Monkey Boy]

6 minutes ago, Deminisher said:

cpuz,etc.. will report what exactly?

Assuming it's running at 1600Mhz, then because of DDR, some applications will report 800Mhz, and others will report 1600MHz.

 

Regardless of dual channel, single channel, quad channel etc... DDR RAM operates with 2 operations per clock cycle. RAM advertised as 1600MHz is actually running at 1600MT/s (1600 Mega Transfers per second) and the actual frequency of the RAM is 800Mhz. Some applications will report the advertised speed (1600Mhz) which is technically a misnomer, while others will report the actual speed (800Mhz). It's up to the user to understand what they are seeing and why.

[Freakwise]

Dual channel will (or atleast should) give you higher overall performance but not higher cpu clock speed

If you want higher cpu clock speed get beefier cooler if you haven't already or overclock it manually

[leadeater]

Topic has been moved to CPUs, Motherboards, and Memory 

[Deminisher]

i think i get it now!? 1-so basically it doesnt really matter what programs report because different programs will report different things 2-the sticks will run at the cpu's 1333 mhz limit right? and finally 3-there will be no performance difference ? did i get that right? ohh so i guess im just gonna pick the stick with the lowest cas latency and speed of 1333 mhz right?

 

Edited June 23, 2021 by Deminisher

[Hairless Monkey Boy]

1 minute ago, Deminisher said:

1-so basically it doesnt really matter what programs report because different programs will report different things

Not really. It matters what they report. But they won't report the data the same way, so you have to know how the application you are using reports the information.

3 minutes ago, Deminisher said:

2-the sticks will run at the cpu's 1333 mhz limit right?

Not necessarily. I don't know about your specific platform, but often times the CPU's max supported memory speed is more of a guideline than a hard limit. Faster RAM is not guaranteed to work, but often times it does.

4 minutes ago, Deminisher said:

3-there will be no performance difference ?

Wrong. Dual channel has nearly twice as much bandwidth as single channel, and can have improved latency too. This may or may not translate into improved performance in the applications that you use, and if it does, the performance improvement may be large or small.

6 minutes ago, Deminisher said:

did i get that right?

Nope.

6 minutes ago, Deminisher said:

so i guess im just gonna pick the stick with the lowest cas latency and speed of 1333 mhz right?

That's probably for the best.

[MageTank]

32 minutes ago, Deminisher said:

hey , i currently have an i5 2430m and while attempting to max it out (upgrade wise)
 a question popped up in my head.,, is it possible for my cpu which can handle upto 1333 max memory speed handle the same speed in dual channel?i was wondering because i currently want to buy two sticks of sodimm ram with speeds of 1600 mhz so ..... in dual channel it should be about 800 mhz so theoritically if i had 2666 sticks in dual channel will they run at my cpu's 1333 supported memory speed or is the supported speed of 1333 mhz only specify single channel and therefore i can have a max mem speed of 666.5,,, btw i know ddr3 doesnt have 2666 mhz sticks i was just wondering if i should pay more for a speed that i wont be able to make use of, thanks in advance!!

 

Everyone in this thread is correct, though I'll try to explain things a bit more in-depth while still keeping it a bit simple for the sake of understanding. The max memory speed supported by your processor is 1333mhz as noted on Intel's ARK page: https://ark.intel.com/content/www/us/en/ark/products/53450/intel-core-i5-2430m-processor-3m-cache-up-to-3-00-ghz.html

 

It also lists the max number of memory channels your processor supports and the max bandwidth that can be achieved by this memory configuration. This page implies that your CPU can officially support 1333mhz in dual channel with a maximum bandwidth of 21.3GB/s (1333 x 8 x 2 = 21,328MB/s or 21.3GB/s). It's important to note that these "limits" are defined by Intel and does not include overclocking beyond their specifications. It's also important to remember that these clock speeds are specifically in regards to what the CPU's memory controller is rated for and have nothing to do with the operating frequency of the processor.

 

5 minutes ago, Deminisher said:

i think i get it now!? 1-so basically it doesnt really matter what programs report because different programs will report different things 2-the sticks will run at the cpu's 1333 mhz limit right? and finally 3-there will be no performance difference ? did i get that right? ohh so i guess im just gonna pick the stick with the lowest cas latency and speed of 1333 mhz right?

 

It's not so much that programs are reporting "different things", but rather they are conveying the same information in two different ways. @Kilrah& @HairlessMonkeyBoyhit the nail on the head here and it's really a matter of preference as to how one chooses to view or define memory frequency. Some will query WMIC MEMORYCHIP GET SPEED, while others will query WMIC MEMORYCHIP GET CONFIGUREDCLOCKSPEED. If you run those two queries, you may get different results entirely. Here is my work computer for example:

 

 

My actual memory frequency is 1200mhz, but it operates at 2400MT/s. We would call this a 2400mhz "effective clock" for simplicity sake. 

 

As for whether there is a performance difference, the answer is yes. As others have stated, dual channel offers up to twice the theoretical memory bandwidth as single channel, though it's important to note this doesn't mean your everyday applications will double in performance. Not everything is sensitive to memory bandwidth and having more than what you need typically doesn't help all that much. Latency is always nice to reduce, but that is an entirely different topic. I would say typical gains from dual channel in gaming/typical use would range from 5-15% depending on the workload and in more bandwidth intense workloads you'd see far more extensive gains. 

[Deminisher]

10 minutes ago, HairlessMonkeyBoy said:

Not really. It matters what they report. But they won't report the data the same way, so you have to know how the application you are using reports the information.

Not necessarily. I don't know about your specific platform, but often times the CPU's max supported memory speed is more of a guideline than a hard limit. Faster RAM is not guaranteed to work, but often times it does.

Wrong. Dual channel has nearly twice as much bandwidth as single channel, and can have improved latency too. This may or may not translate into improved performance in the applications that you use, and if it does, the performance improvement may be large or small.

Nope.

That's probably for the best.

oops im extremely bad with words... , oh and i was talking about the difference between 1333 mhz ram in dual channel vs 1600 mhz in my specific case, pretty sure most people know that dual channel is pretty much just better

 

[mariushm]

You're full of confusion.

 

On every Hz , the memory sticks transfer 2 bits on every data pin. The memory stick is 64 bit wide (64 data pins), so there's 128 bits transferred with every Hz between the ram stick and the memory controller.

 

In order to differentiate these DOUBLE DATA RATE memory sticks (which put 2 bits on every data pin on each Hz) from SDRAM (older ram sticks, which are single data rate, one bit per pin) the ram stick manufacturers simply started to advertise the sticks at double the frequency they actually work at.

So, a  DDR3-1600 Mhz memory stick actually runs at 800 Mhz  but it's sold as 1600 Mhz because it can transfer twice the amount a 800 Mhz SDRAM stick would.

 

In dual channel mode, the memory controller reads and writes from both channels at the same time instead of using a single stick.

So, on every Hz, it can do 128 bits on first channel (first stick)  and 128 bits on second channel (second stick) so a total of 256 bits on every Hz.

 

If you want to store 1 MB of data into RAM, the memory controller writes in parallel 512 KB to first stick, 512 KB to second stick, so the transfer is done in nearly half the time, but the memory sticks and the memory controller still run at the same frequency (800 Mhz for my example of DDR3-1600 sticks)

 

===

I'll simplify things a lot a bit to the point that some things may be incorrect, but for a very noob about these it's probably good enough.

In computers (and processors), components have to synchronize somehow, so there's clocks (frequencies) used to achieve this. There's a base frequency, typically between 100 Mhz and 200 Mhz, often called Front-Side Bus :https://en.wikipedia.org/wiki/Front-side_bus

 

From this base frequency the computer uses multiplier and divider circuits to produce other frequencies ... for example 100:3 or 200:6 gives you 33.33 Mhz which is the frequency of old PCI (before AGP and PCI-e),  AGP run at 66 Mhz, which is achieved by diving 200 by 3 ...pci-e bus runs at 100 Mhz. 

 

In order to get high frequencies like 3-4 Ghz, processor uses a multiplier, typically a multiplier can jump in 0.5x intervals ... so for example, in the case of my FX-8320 which has a base bus frequency of 200 Mhz, it can jump up and down in 100 Mhz steps ( see picture below)

 

Just the same, in order to sync with the memory, there's a multiplier and/or divider used to generate the frequency ram runs at from that base cpu frequency.

In my case where my CPU has a base 200 Mhz frequency and my RAM is currently running at DDR3-1333 for some reason (probably reset bios to defaults at some point and forgot to set it back to 1600), you can see there's a FSB:DRAM ratio of 3:10   :

 

 

You can see that the processor's FSB frequency is 199.99 Mhz  so the 666.66 Mhz frequeny of my RAM is generated from that :  199.99 x 10 / 3 = 666.633 Mhz which is close enough.

The clock which generates the FSB can vary by a tiny amount with temperature and other factors, and on some high end motherboards the FSB may be on purpose set above the standard value and it's considered a minor overclocking. 

Note though that because of these multipliers and dividers, other buses can be affected if one attempts too much of a change, so for example the pci-e's 100 Mhz bus frequency may drift to a point where your video card could crash or reset.