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i have intel p4 2.4ghz real clock is 100 mhz and fsb is 400mhz and my ddr3200 ram real clock is 200 double 400mhz i mean double is 400mhz
i set my ram frequency to 400mhz to match with my cpu fsb which is 400mhz but my pc failed to work i mean it starts but screen is blank so i set default setting can anyone tell me y i can set my memory clock to 400mhz i want to match cpu and memoy clock for maximum performance
i can select 200mhz 233mhz and 333mhz and all these 3 works fine i cant use 400 i mean i did select 400mhz but it wont work
my cpu is always set to auto is that auto thing wont let my memory work on 40mhz???
Work the the real numbers, not the theoretical ones. And for optimal performance, the CPU:DRAM ratio should be 1:1.
Your CPU runs at 100MHz, so your RAM should run at 100MHz. Use the 200MHz setting then confirm your settings are correct by running CPUZ
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i dont agree with u my cpu real clock is 100mhz but external clock is 400mhz so i have to match my cpu external clock which is also called fsb 400mhz with memory clock memory clock 200 but double is 400mhz
cpuz says my fsb is 400mhz and real clock is 100mhz
hers in detail what cpuz says
bus speed:100 mhz
rated fsb 400mhzso did u see my fsb is 400 and ddr400 rated clock is 400mhz then y it wont work when i seletch 400mhz for memory clock???
is that not true that cpu fsb clock and memory clock should match???
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the website hardwaresecret says match ur cpu external clock with memory clock not the real clock
read this plzSo you need to known your CPU external clock rate to know which is its maximum transfer rate. The best way to check this is running CPU-Z software, available on our download section. Run it and check the external clock speed of your CPU on the "Bus Speed" field and check what is its maximum transfer rate on the table above
As we said before, once you know the maximum external transfer rate of your CPU it is just a matter of matching the memory transfer rate with it
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Your 2.4GHz CPU runs at 100MHz, not 400MHz. Simply look at the clock settings...it's 24 x 100MHz, not 6 x 400MHz. The 400MHz number is theoretical & is based on Intel's "quad-pump" technology.
Same goes for your RAM. DDR400 runs at 200MHz, not 400MHz. The 400MHz number is theoretical based on "double-pump" technology.
As I said above, running the CPU:DRAM ratio at 1:1 is ideal. In your case it would be 100:100. If you run the CPU at 100MHz & the RAM at 200MHz, your ratio is 100:200 (or 1:2) & system performance will suffer.
"This solution, however, isn't ideal. Running the FSB and RAM with a ratio [other than 1:1] causes gaps in between the time that the FSB can communicate with the RAM. This causes slowdowns that wouldn't be there if the RAM and the FSB were running at the same speed. If you want the most speed out of your system, using an FSB:RAM ratio wouldn't be the best solution."
http://www.eliteb---tards.com/cms/in...
Here is someone who put the "1:1 ratio is best" theory to the test:
"Well there has been a lot of discussion as of late regarding Multipliers, FSB:RAM Dividers, and performance thereof. Some have argued that running a divider will increase performance by allowing higher RAM frequencies. No one will argue that higher Memory frequencies mean higher bandwidth (and thus, higher performance) as a general rule. But I have argued that if you are capable of obtaining a Front Side Bus at the same speed as your RAM (well, half, speaking in terms of DDR of course), that you should keep a 1:1 ratio. In my opinion, running at a ratio that is "out of sync" will deter performance."
http://www.overclock.net/intel-cpus...
Here's another discussion about ratio...this time regarding an Intel CPU w/1066MHz FSB (266MHz actual) & DDR-800 RAM (400MHz actual):
"The FSB to RAM ratio is just that. 266:400=2:3. That's where the ratio comes from. The problem is that when the FSB and the RAM run at different frequencies, they are not syncronyzed. (Obviously) So there is a slight performance loss in the process to get the two out-of-sync frequencies back in sync, so they communicate. To eliminate this why not run the RAM at the same speed as the FSB? That's what the 1:1 ratio does. So if the FSB is 266MHz, the actual RAM speed is 266MHz, which is "effectively" 533MHz, or DDR2-533. So if you change the FSB to 300MHz, you CPU is 7x300=2100MHz, and RAM is 2x300MHz, or DDR2-600. OK?"
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u mean that hardwaresecrets website is wrong about cpu and ram running same frequency r they wrong when they said match ur cpu fsb with ram rated speed
they reviewed dual core e6750 and said they need DDR3-1333 to match with cpu fsb
ddr3-1333 real clock is 166mhz but effective is 1333mhz.so if i have a e6750 processor i need ddr3-1333 memory to match with this processor fsb which is also 1333mhz thats website claim not mine r u saying they r wrong???????
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plz read what this website says
The second reason we can see is regarding DDR3-1333 memories, which will be supported by the Intel X38 chipset to be launched in July. Using DDR3-1333 memories with a Core 2 running externally at 1,333 MHz you will be able to match the FSB clock with the memory clock, allowing you to achieve the maximum performance with current technology
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so what i tried to do is i set my memory freuquency to 400mhz under bios to match with my cpu fsb which is 400mhz i know my cpu real clock is 100mhz but we need to match cpu fsb clock with memory rated clock for example ddr3200 real is 200 but rated is 400mhz but when i seletcted 400mhz under bios my pc failed to work thats what im asking y it didnt work do u understand now
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ddr3 1333 matchs with e6750 fsb just like my memory ddr3200 400mhz matchs with my cpu fsb 400mhz
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gunfun
One post and then wait for responses. jam is correct. I don't need to read the article you refer to. As jam said, look at your clock settings in the BIOS to see the actual FSB of your system. DDR3200 isn't even the correct name for that memory. It is DDR400 OR PC3200. The 3200 refers to the bandwidth. DDR stands for Double Data Rate. The RAM is charged twice each cycle.
You probably need to read up on this stuff more.
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If you drive you car (alone) at 100MPH, how fast is it going?
If you drive you car at 100MPH & have one friend with you, how fast is your car going? 100MPH or 200MPH?
If you drive you car at 100MPH & have 3 of your friends with you, how fast is your car going? 100MPH or 400MPH?
100MPH is 100MPH, it's not 200MPH or 400MPH.
If you have an Intel 400MHz FSB CPU (100MHz), your RAM should also run at 100MHz to stay in sync. If doesn't matter if your RAM is DDR266, DDR333, DDR400, etc. to run it in sync with the CPU, it should be underclocked to DDR200 speed (100MHz). That way, you'll have the optimal 1:1 ratio.
Since you obviously don't believe me & no number of links I post will convince you otherwise, try testing the theory yourself, just like the guy from overclock.net did.
Leave the CPU freq set at 100MHz, leave the RAM timings at the defaults, set RAM at DDR200 (100MHz) & run 3DMark. Run it four times & take the average. Repeat the test with the RAM set to DDR266 (133MHz), DDR333 (166MHz), DDR400 (200MHz).
http://www.futuremark.com/download/
Post back with your results.
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when i said 3200 i meant pc3200 which is ddr4000 all know that ok and jam is wrong that website is from professionals and i checked my fsb with cpuz it says my rated fsb is 400mhz and bus speed is 100mhz jam is wrong
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Well then follow what you KNOW is true and try setting the DDR to 400. Good luck with that.
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i did test i set my ram frequency to 400mhz but it didnt work anyways just answer 2 questions
first
that website hardwarescret saying for best performance cpu fsb and memory clock should match r they wrong or lying???if i have e6750 cpu with fsb 1333mhz and a ram ddr3-1333 what frequency should i select under bios???
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READ THESE LINES FROM PROFESSIONALS R U ALL BLIND HUH
The second reason we can see is regarding DDR3-1333 memories, which will be supported by the Intel X38 chipset to be launched in July. Using DDR3-1333 memories with a Core 2 running externally at 1,333 MHz you will be able to match the FSB clock with the memory clock, allowing you to achieve the maximum performance with current technology
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Again, you aren't running DDR3 memory. The settings for that RAM are different than yours.
Look at the link below. On the right side of the page the are listings for DDR, DDR2, DDR3. Read all and learn.
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e6750 real clock is 333mhz and ddr3-1333 rated clock is 166mhz they dont match i know but this cpu fsb 1333mhz and memory rated clock 1333mhz matchs thats y they want ddr3-1333 for e6750 do u understand????
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In retrospect we must keep in mind that this is the first time in six years that Intel is launching a new front side bus speed with memories matching it. When the Pentium 4 was launched, for example, it used the then-new 400 MHz FSB and there were no 400 MHz memories at the time – this was PC-100 times and DDR-400 wasn’t available yet. The same thing happened when they launched the 533 MHz, the 800 MHz and even the 1,066 MHz external clock speeds. Even to this date Intel chipsets do not officially support DDR2-1066 (even though Intel P965 and P35 can access memories at 1,066 MHz just fine and P35 officially support DDR3-1066). DDR3-1333 availability may be an issue, but that is a totally different story.
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The proof is in the pudding:
"i set my ram frequency to 400mhz to match with my cpu fsb which is 400mhz but my pc failed to work"
If your way of thinking is correct, why is it that can't you get your system to work that way?
"if i have e6750 cpu with fsb 1333mhz and a ram ddr3-1333 what frequency should i select under bios???"
I don't know why this is so difficult to understand?
The E6750 has a CPU freq of 333MHz, therefore you need RAM that's capable of at least 333MHz...that would be DDR2-667 or better. Even if the board supports DDR3-1333 (667MHz), it should be clocked down to 333MHz to match the CPU freq. And running RAM below it's rated speed has the benefit of allowing the RAM timings to be tightened up, & that even adds more to system performance.
I have deliberately not mentioned running the RAM in dual channel mode because I don't think you're capable of understanding, but since you insist on getting info from "professionals", do you think Tom's Hardware qualifies?
"Dual-channel mode allows a pair of DDR2 modules at 533 MHz data rate to provide the same bandwidth as Intel's FSB1066, and keeping memory at a 1:1 ratio with the CPU will assure adequate performance up to the overclocking limit of the CPU or RAM."
"For FSB1066 Core 2 Duo CPUs, this means that DDR2-800 could be underclocked to 533 MHz data rate without a significant performance loss, while increasing the CPU to FSB1600 - though difficult - would only bring the RAM back up to its rated speed."
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