DRAM:FSB ratio question

By Lightwave
Aug 14, 2010
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  1. Hi, i just bought a new PC with the following components:

    Motherboard - Asus P7P55D
    CPU - Intel Core i5 750 2.66
    RAM - A-DATA DDR3 1600X 2x2GB Memory Kit

    My question is about the memory, Everest shows a dram:fsb ratio of 5:1 and that the memory is running at 667 MHz. Is this ratio supposed to be normal? I though a ratio of close to 1:1 is usually desired. Also the Front Side Bus clock speed is 133 MHz. Here's the report from Everest:

    Code:
          Motherboard Name                                  Asus P7P55D
    
        Front Side Bus Properties:
          Bus Type                                          Intel QPI
          Real Clock                                        132 MHz
          Effective Clock                                   132 MHz
          QPI Clock                                         2393 MHz
    
        Memory Bus Properties:
          Bus Type                                          Dual DDR3 SDRAM
          Bus Width                                         128-bit
          DRAM:FSB Ratio                                    5:1
          Real Clock                                        660 MHz (DDR)
          Effective Clock                                   1319 MHz
          Bandwidth                                         21107 MB/s
    
        Motherboard Physical Info:
          CPU Sockets/Slots                                 1 LGA1156
          Expansion Slots                                   3 PCI, 2 PCI-E x1, 2 PCI-E x16
          RAM Slots                                         4 DDR3 DIMM
          Integrated Devices                                Audio, Gigabit LAN, IEEE-1394
          Form Factor                                       ATX
          Motherboard Size                                  240 mm x 300 mm
          Motherboard Chipset                               P55
          Extra Features                                    JumperFree, Q-Fan, Stepless Freq Selection, Ultra-ATA/133, SATA-II
    
  2. CMH

    CMH TechSpot Chancellor Posts: 2,572   +9

    The 1:1 ratio was desired in the times of the Conroe.

    However, I am equally interested in this question for the Nehalem family.

    I don't think it is possible to get 1:1 with this chip.
  3. raybay

    raybay TechSpot Evangelist Posts: 10,716   +6

    Is it working right for you?
    Does the ratio seem to make any difference?
    The stats you show are decent, or better.
    You took yourself out of the extreme high performance area when you chose A-Data, but if your games and graphics software still play nice, that is all you need. Right?
  4. Lightwave

    Lightwave Newcomer, in training Topic Starter

    Also I expected the memory to run at 800 MHz, not 667, since it's supposed to be DDR 3 @ 1600 MHz (PC3-12800) as per the official web site:
    oc.adata.com.tw/1_product_detail.asp?pid=AD31600XU2K (sry, can't post links yet)

    cpuz lists it as PC3-10700 (667 MHz), weird..

    Code:
    DIMM #				1
    	SMBus address		0x50
    	Memory type		DDR3
    	Module format		UDIMM
    	Manufacturer (ID)	A-Data Technology (7F7F7F7FCB000000)
    	Size			2048 MBytes
    	Max bandwidth		PC3-10700 (667 MHz)
    	Part number		DDR3 1600X        
    	Number of banks		8
    	Nominal Voltage		1.50 Volts
    	EPP			no
    	XMP			yes
    	XMP revision		1.2
    JEDEC timings table		CL-tRCD-tRP-tRAS-tRC @ frequency
    	JEDEC #1		6.0-6-6-17-23 @ 457 MHz
    	JEDEC #2		7.0-7-7-20-27 @ 533 MHz
    	JEDEC #3		8.0-8-8-22-30 @ 609 MHz
    	JEDEC #4		9.0-9-9-25-34 @ 685 MHz
    XMP profile			XMP-1334
    	Specification		PC3-10700H
    	Voltage level		1.400 Volts
    	Min Cycle time		1.500 ns (667 MHz)
    	Min tRP			13.50 ns
    	Min tRCD		13.50 ns
    	Min tWR			15.00 ns
    	Min tRAS		36.00 ns
    	Min tRC			49.50 ns
    	Min tRFC		110.00 ns
    	Min tRTP		7.50 ns
    	Min tRRD		6.00 ns
    XMP timings table		CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
    	XMP #1			5.0-5-5-14-19-0T @ 370 MHz (1.400 Volts)
    	XMP #2			6.0-6-6-16-22-0T @ 444 MHz (1.400 Volts)
    	XMP #3			7.0-7-7-19-26-0T @ 518 MHz (1.400 Volts)
    	XMP #4			8.0-8-8-22-30-0T @ 592 MHz (1.400 Volts)
    	XMP #5			9.0-9-9-24-33-0T @ 666 MHz (1.400 Volts)
    XMP profile			XMP-1600
    	Specification		PC3-12800
    	Voltage level		1.650 Volts
    	Min Cycle time		1.250 ns (800 MHz)
    	Min tRP			8.75 ns
    	Min tRCD		8.75 ns
    	Min tWR			15.00 ns
    	Min tRAS		25.00 ns
    	Min tRC			43.75 ns
    	Min tRFC		110.00 ns
    	Min tRTP		7.50 ns
    	Min tRRD		5.50 ns
    XMP timings table		CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
    	XMP #1			5.0-5-5-15-25-0T @ 571 MHz (1.650 Volts)
    	XMP #2			6.0-6-6-18-30-0T @ 685 MHz (1.650 Volts)
    	XMP #3			7.0-7-7-20-35-0T @ 800 MHz (1.650 Volts)
    	XMP #4			8.0-8-8-23-40-0T @ 914 MHz (1.650 Volts)
    	XMP #5			9.0-9-9-26-45-0T @ 1028 MHz (1.650 Volts)
    	XMP #6			10.0-10-10-29-50-0T @ 1142 MHz (1.650 Volts)
  5. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 5,847   +64

    your MB may nativley support 1066 memory and defaulted to that speed, it will run at 1600 as OC'ed. change it in the BIOS.
  6. raybay

    raybay TechSpot Evangelist Posts: 10,716   +6

    Not uncommon, in my experience, with A-Data... I have had no failures, but have too often noticed performance issues...
    But then it could be the system board... or elsewhere... Have you tried any of the other test software? Such as Sandr Lite 2010 SP2, SiSoft Sandra, Speccy, 3DMark Vantage or 3DMark03, 05, 0r 06
    Everestm GPU-Z, SpeedFan, to see how everything fits together ?
  7. Lightwave

    Lightwave Newcomer, in training Topic Starter

    So I figured it out. You're right. Actually it defaults to 1333 and will run at 1600 only if OCed, I'd have to increase the FSB clock from 133 to 160 MHz and overclock the CPU from 2.66 to 3.2 GHz. I'm not really going to do it for now since I'm happy with the performance, anyway.

    Thanks all.
  8. Lightwave

    Lightwave Newcomer, in training Topic Starter

    double post, please delete this


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