Archived from groups: alt.comp.hardware.homebuilt (
More info?)
Jim:
I would like to thank you sincerely for "taking me to school" this
evening. It is not often at my age (66) that I get the chance to
absorb so much new information. By printing out your posts and
sitting with them I learned quite a bit tonight.
Thanks again.
Gary
On Sun, 11 Apr 2004 14:57:26 -0700, "Jim" <null@null.com> wrote:
>Note: The "ratio status" field is NOT DRAM related, that's the "multiplier"!
>You take the CPU FSB 200MHz, multiple it the multiplier and get the CPU
>speed (200 x 11 = 2.2GHz). It says "locked" because Intel multiplers can't
>be altered, which some people do alter (if unlocked) to overclock the CPU.
>
>Btw, I should add, that "chipset limitation" it refers to? Guess what that
>is? It's the lack of a CPU/DRAM ration option for PC2700 with your CPU FSB
>200 (800) that I alluded to earlier!
>
>I'm not familar w/ your Asus mobo specifically, each motherboard BIOS setup
>varies from vendor to vendor. On some motherboards, you set a CPU/DRAM
>ration directly (e.g., 1:1, 5:4, 3:2). The ratios available change
>depending on the CPU FSB. With other vendors, these ratios are *implied* by
>the memory options listed for a given CPU FSB (as decribed in that chart).
>In your case, look under Advanced Chipset Options, that's the DRAM Freq
>field. IOW, some vendors provide ratio settings, others limit the displayed
>memory options (266, 333, 400). It's all the same in the end.
>
>Asus motherboards are limited in supported CPU/DRAM ratios, just like any
>other motherboard, and those limitations are reflected in that chart that
>states what memory combinations are supported. In your case, depending on
>the CPU FSB installed, the DRAM options available change. Although PC2700
>is listed w/ CPU FSB 200 (800), it's the lack of a specific CPU/DRAM ratio
>(even though you can't see it) that is limiting the full exploitation of
>your PC2700. Using your current CPU FSB 200 (800), in order to support
>PC2700 *fully*, would require a CPU/DRAM ration of 6:5 (200 / 6 * 5 = 166).
>Problem is, that ratio is not supported by the chipset at CPU FSB 200MHz
>(800)!!! But the nearest available CPU/DRAM ratio that *is* available is
>5:4 (very common), which is (200 / 5 * 4 = 160, x 2 (DDR) = 320). Whalla,
>there's where the 320MHz came from!
>
>That's a long way of simply confirming my initial suspicions, there just
>isn't a CPU/DRAM ratio available of 6:5 on the Intel chipset in order to
>support your PC2700 at CPU FSB 200 (800), not at 333MHz DDR anyway. The
>best available is 5:4, which results in underclocking your memory. The only
>difference between your Asus motherboard and my Abit motherboard using the
>same chiptset is, my Abit motherboard uses and shows CPU/DRAM ratio
>settings, your Asus doesn't, it takes a different approach and only displays
>the available memory options. But it's six of one, half a dozen of the
>other.
>
>In the end, it's what I said initially, you can't just put any memory
>together with any CPU FSB, not without sometimes causing one or the other to
>be over/underclocked to keep within the CPU/DRAM ratios supported. When you
>mix something like the CPU FSB 200 (800) and PC2700, the motherboard does
>the only thing it can do -- underclocks the memory so it can use the 5:4
>CPU/DRAM ratio. The only other choice would be to underclock the CPU (run
>it 166MHz, or 333MHz DDR). Now the motherboard can apply the 1:1 CPU/DRAM
>ratio, everything runs "in sync", and all is happy. Of course, this is not
>what most people want, they want the CPU to run full speed, so the
>motherboard underclocks the memory instead. But nothing stops YOU from
>underclocking the CPU if you want, your PC2700 will now run at FULL SPEED!
>It might be interesting to compare the results! You *might* possibly get
>better performance!
>
>HTH
>
>Jim
>
>
>"Gary B. Berns" <gberns@tampabay.rr.com> wrote in message
>news:j3bj70hg3or189shegkrkpcq9er2reok1p@4ax.com...
>> Should have done this before writing last reply. Went into bios. It
>> states CPU has 400 FSB with ratio status locked. Under the memory
>> setup, my option was auto or 266 which according to manual backs up
>> what I said about memory not being PC2700 which you, if I understand
>> what you wrote, say makes no difference to me.
>>
>> Not that I would play with it, but I do not see any place to adjust
>> ratio between memory frequency and CPU FSB unless it's in the section
>> dealing with DRAM timing by SPD which I have set as disabled.
>>
>> Gary
>>
>> On Sun, 11 Apr 2004 11:41:48 -0700, "Jim" <null@null.com> wrote:
>>
>> >Hmm..., well, since you didn't mention your CPU, and thus we don't know
>the
>> >FSB, it's not clear that PC2700 is indeed ideal. Beware, you pay a
>> >considerable performance penalty for NOT keeping your CPU FSB and memory
>> >speed in sync. Use of PC2700 (333MHz DDR, 166MHz actual) *implies* that
>you
>> >are probably (or should be) running 166MHz FSB. But since Intel does not
>> >produce 166MHz CPUs, it means that really you either have a 100MHz,
>133MHz,
>> >or 200MHz FSB on your CPU (or in "quad-pumped" terms, Intel 400MHz,
>533MHz,
>> >or 800MHz). IOW, PC2700 is not a proper/ideal match for *any* CPU that
>> >Intel currently produces! So presumably you're running async.
>> >
>> >The *ideal* CPU/memory choices are:
>> >
>> >CPU FSB = 100, PC1600
>> >CPU FSB = 133, PC2100
>> >CPU FSB = 200, PC3200
>> >
>> >All these are "sync" (1:1). Notice there's no place for PC2700. Not
>unless
>> >you run async.
>> >
>> >And PLEASE, noone chime in about OC'ing here, we're talking strictly
>"spec",
>> >to keep the conversation as simple as possible (I just know someone in
>the
>> >crowd will hammer me on something like this, never fails).
>> >
>> >But, be that as it may...
>> >
>> >As far as "seeing" only 266MHz, this gets back to what I said above. In
>> >order to keep the CPU FSB "at spec", something has to give, so perhaps
>the
>> >memory is being UNDERclocked purposely. For example, if the CPU FSB is
>> >133MHz, and the default/preferred CPU/DRAM ratio is 1:1, PC2700 memory
>will
>> >be underclocked to PC2100 to maintain sync (hence, perhaps the 266MHz you
>> >see). PC2700 is 166MHz, and in order to run it at full speed w/ the CPU
>FSB
>> >133MHz, the CPU/DRAM ration would need to be 5:6 (133 / 5 * 6 = 166).
>Heck,
>> >I don't even know if your motherboard provides a 5:6 option, the chipset
>> >sometimes can't run every ratio you would might like! So if 5:6 is not
>even
>> >AVAILABLE, the motherboard will have no choice but to underclock that
>PC2700
>> >to PC2100, esp. since it prefers sync (1:1) anyway.
>> >
>> >Of course, I'm using these numbers as an example, you didn't mention the
>CPU
>> >FSB, so I speculated, but its the principles/concepts that are most
>> >important here. The point I'm getting at is, you need to be sure that
>you
>> >have the ideal/best choice of memory for your particular motherboard/CPU,
>> >not just some arbitrary choice on what *sounds* like enough, it has to be
>> >more precise and deliberate. You may not even be able to run some
>> >combinations on your motherboard when the CPU FSB and memory speeds are
>> >different unless a) you have an appropriate CPU/DRAM option available or
>b)
>> >unless you're willing to over/underclock the CPU FSB or memory to bring
>it
>> >all back into sync (1:1), should an appropriate CPU/DRAM ratio not be
>> >available.
>> >
>> >And don't be mislead by the motherboard specs, yes it can support many
>> >speeds of CPU FSB and memory, but that's NOT to say it can do so in ALL
>> >combinations! Maybe so, maybe not.
>> >
>> >HTH
>> >
>> >Jim
>> >
>> >
>> >"Gary B. Berns" <gberns@tampabay.rr.com> wrote in message
>> >news:6l0j709vi6dn1v6kqj9pdkcu7jdcockr06@4ax.com...
>> >> Just installed a new Asus P4P800-VM motherboard and put in a new PNY
>> >> 512 mg memory which was supposed to be PC 2700. Bought on EBay. That
>> >> is why I said "supposed to be." Bios originally read it as 512 meg at
>> >> 266 speed. So much for the PC 2700. I day or so later Bios started
>> >> to read it as 504 meg. Bios is now reading it as 480. Computer seems
>> >> to be running all right.
>> >>
>> >> Can someone advise what is going on? Aslo reccommend a reasonably
>> >> good PC2700 memory to replace what I have in there. Although the
>> >> board will take DDR400 I do not do anything which needs it and have no
>> >> intention of overclocking.
>> >>
>> >> Thanks.
>> >>
>> >> Gary
>> >
>>
>
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