(1) What is a Athlon 64 Desktop Replacement (DTR) CPU?
(2) Are their different types of Athlon 64 mobile processors?
(3) Is that every mobile CPU available?
(4) What is the difference between the mobile Athlon 64s and the desktop revision Athlon 64s
(5) So, I want to go mobile, but which CPU should I choose?
(6) Do I need to run 1:1 memory to achieve peak performance on the Athlon 64?
(7) What motherboards work properly with a mobile Athlon 64?
(8) Do any Micro ATX motherboards with mobiles?
(9) Do any SFF Socket 754 systems work with mobiles?
- It's a mobile version of the Athlon 64 desktop processor
(2) Are their different types of Athlon 64 mobile processors?
- There are three types (all using the same Socket 754 interface as the desktop Athlon 64):
- (a) The 1.5v DTR CPUs come in four flavors currently, a 3700+ model with a clock speed of 2.4Ghz and 1MB of L2 cached with the improved CG revision core, a 3400+ model with a clock speed of 2.2Ghz and 1MB of L2 cache with the improved CG revision core, a 3200+ model with a clock speed of 2.0Ghz and 1MB L2 cache with the improved CG revision core, and a 3000+ model with a clock speed of 1.8Ghz and 1MB L2 cache with the improved CG revision core.
(b) The 1.4v "mobile" CPUs which are basically just DTR CPUs rated to run at a lower default voltage (although the CG DTR 3200+ will also run at 1.4v with complete stability) These CPUs come in four flavors, a 3400+ model with a clock speed of 2.2Ghz and 1MB of L2 cache with the improved CG revision core, a 3200+ model with a clock speed of 2.0Ghz and 1MB L2 cache with the improved CG revision core,a 3000+ model with a clock speed of 1.8 Ghz and 1MB L2 cache with the improved CG revision core, and a 2800+ model with a clock speed of 1.6Ghz and 1MB L2 cache with the improved CG revision core.
(c) The 1.2v "true mobile" CPUs. There are two models, a 2800+ model with a clock speed of 1.8Ghz and 512k L2 cache with the improved CG revision core, and a 2700+ model with a clock speed of 1.6Ghz and 512k L2 cache with the improved CG revision core.
Further information regarding the CPUs listed above can be found in AMD's Athlon 64 Processor Power and Thermal Data Sheet:
http://www.amd.com/us-en/asset...nd_tech_docs/30430.pdf - (a) The 1.5v DTR CPUs come in four flavors currently, a 3700+ model with a clock speed of 2.4Ghz and 1MB of L2 cached with the improved CG revision core, a 3400+ model with a clock speed of 2.2Ghz and 1MB of L2 cache with the improved CG revision core, a 3200+ model with a clock speed of 2.0Ghz and 1MB L2 cache with the improved CG revision core, and a 3000+ model with a clock speed of 1.8Ghz and 1MB L2 cache with the improved CG revision core.
(3) Is that every mobile CPU available?
- According to AMD technical documents it is not. All the CG core processors except for the DTR 3700+ and the 1.2v true mobile CPUs appear to be available in the older C0 revision core. To ensure that one is getting a CG core check the processor part number and make sure it ends with either -AR or -AX as shown here:
http://www.amdboard.com/amd64_opn.html
(4) What is the difference between the mobile Athlon 64s and the desktop revision Athlon 64s
- (a) Both CPUs feature a multiplier half lock. In other words, like the desktop chip, the mobile chips' multiplier is locked at a maximum number but unlocked for all lower multipliers down to 4x.
(b) The mobile processors are typically, newer CG revision CPUs. Most desktop CPUs with 1MB of L2 remain the older C0 revision; even some CPUs, typically the lower end 2800+ and 3000+ desktop CPUs with only 512k of cache are the older C0 revision. The advantages to the CG revision is that it runs much cooler than the C0 revision chips. Max TDP for the line of C0 revision cores is 89W compared with a max TDP of 81.5W for the CG revision cores. The CG revision of the Athlon 64 also overclocks better than current desktop C0 revision chip. The CG revision CPUs also feature an improved memory controller for better memory performance and compatability. In essence, if you're looking for the best performance out of the Athlon 64 Socket 754, you need to find a 1MB L2 cache CG revision chip, and those chips are exceedingly rare outside of the mobile CPU realm.
(c) Because the mobile Athon 64 CPUs are not desktop processors even though they can physically fit in the desktop socket, the BIOS of the motherboard you want to use must recognize the microcode. Otherwise the system will either fail to boot (most common problem) or the CPU will lock down to 800mhz (4x mutliplier).
(d) The mobile CPUs lack the Integrated Heatspreader (IHS) common to the desktop processors. This allows better cooling of the CPUs as heatsink contact is directly with the CPU core itself. But as a result of this, the CPUs are "shorter" than their desktop counterparts and heatsink contact is a very real concern. Most backplates, whether included with the motherboard or the ones AMD includes with their retail chips will not work properly - the screw poles aren't deep enough. Only one heatsink setup works properly without modification with the mobile CPUs, the Thermalright SLK-948U Heatsink.
(5) So, I want to go mobile, but which CPU should I choose?
- Here are some factors to consider:
- (a) The difference between 1MB of L2 cache and 512k of L2 cache at the exact same speed is approximately 5%. What that means is that you would need for example a 2.1Ghz 512k L2 cache Athlon 64 to equal the performance of a 2.0Ghz 1MB L2 cache Athlon 64. So, obviously since all CG cores overclock to the same range, 2.4-2.5Ghz on aircooling, one should prefer a CPU with a full 1MB of L2 cache.
(b) Get a CG core. Simple. They overclock better and run cooler
(c) Given the choice, the obvious CPUs to select are the 3200+ DTR or any of the 1.4v mobile CPUs. These all feature a full 1MB of L2 cache for maximum performance. Please note that the lower the speed the lower the mutliplier of the chip and the higher the HTT/FSB needed to get a succesfully overclock into the 2.4-2.5Ghz range.
(d) Wait, but aren't the 1.4v mobile Athlon 64s much cooler running than the DTR processors? Actually, no they're not. Remember that when AMD rates thermal output they only give the max output for the single top of the food chain CPU. Thus, for the desktop and mobile C0 revision, the highest is a 3400+ at 89W. For the CG revision DTRs the highest is a 3400+ at 81.5W. Now here's where you need to pay attention. The highest CG revision 1.4V mobile CPU is the 3200+ and NOT the 3400+ so the TDP listed of 62W cannot be compared to the other CPUs. In fact, if you compare it to the DTR CPUs and do a little guestimation (don't know if there's a linear relationship between clockspeed and heat) you'll see that these are basically CG DTR CPUs running at 1.4V These are just rebranded DTR CPUs.
(e) But still, shouldn't the 1.4v mobiles overclock higher than the CG DTR? Not at all. Given the choice there's no reason to not pick up the 1.4v mobiles but all CG revision CPUs hit a wall at ~2.5Ghz with aircooling, whether they default at 1.5v, 1.4v, or even 1.2v
- (a) The difference between 1MB of L2 cache and 512k of L2 cache at the exact same speed is approximately 5%. What that means is that you would need for example a 2.1Ghz 512k L2 cache Athlon 64 to equal the performance of a 2.0Ghz 1MB L2 cache Athlon 64. So, obviously since all CG cores overclock to the same range, 2.4-2.5Ghz on aircooling, one should prefer a CPU with a full 1MB of L2 cache.
(6) Do I need to run 1:1 memory to achieve peak performance on the Athlon 64?
- Not really, given the Athlon 64 architecture and the integrated memory controller, there is no statistically significant advantage to running memory at a 200 setting versus a 166 setting at, for example, around DDR400 speeds. Even at the 200 setting the memory in an Athlon 64 system is running async. The memory speed is arrived at by using a divisor off the Athlon 64 CPU speed (i.e. a /12 divisor.) Also, unlike the Pentium 4, the Athlon 64 is not bandwidth starved; thus, the difference in memory speeds between DDR400 and DDR 500 is at most 1-2% IF you're running at the same timings, otherwise the relaxing of the timings will wipe out even that small gain. In other words, don't go crazy and throw away perfectly good PC3200 RAM thinking you'll see a significant boost using DDR500 for example; you won't, and your wallet will hurt.
(7) What motherboards work properly with a mobile Athlon 64?
- As of right now, only the below listed motherboards are confirmed to work to varying degrees; with the worst offenders requiring software hacks. Please note that the DTR and Mobile and True Mobile CPUs (the latter two are the "mobile CPUs" referred to in the rest of the paragraph) have different microcode. At the current time the implication of this is not fully known. Upon initial testing, it seems that support for a DTR CPU does not guarantee proper support for mobile CPUs (e.g. the CPU may be properly recognized but multiplier and/or voltage may no longer be modifiable.) On the other hand, support for mobile CPUs seems to indicate full support for the DTR CPUs. Again, these are just initial findings and more compatability testing is needed before this can be confirmed. In the future more motherboards will be added should they be found to be compatible with the mobile Athlon 64 processor.
- LEGEND
AGP/PCI lock = working AGP/PCI lock. This allows for maximum overclocking
FID = muliplier control, from 4x to the maximum multiplier of the particular CPU. Useful for those looking to eek out every last drop of performance through high HTT
HTT = hypertransport bus speed is adjustable. Think of this as a frontside bus speed. The processor speed is arrived at by multiplying the HTT by the FID
Vcore = CPU voltage is adjustable
Vdimm = memory voltage is adjustable
LDT = HTT multiplier is adjustable. Different than FID. Sometimes overclocking necessitates that you lower this.
- (a) SiS 755/964
- ASRock K8S8X [AGP/PCI Lock, FID 4x-Max, HTT adjust, VCore, LDT; Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.4v] - If your shipping BIOS is 1.50 then the board will boot fine but lock down to a 4x multiplier (800Mhz speed). You'll also get an error and have to go into the BIOS. Discard changes and exit and it should continue the boot cycle. At that point you should already have a Win95/98 boot disk in there with another floppy with the flash program and the latest 1.70 BIOS. If your shipping BIOS is 1.60 you shouldn't have to do anything but if you're running a 1.4v mobile CPU you need to update to the latest 1.70 to allow multiplier control if desired. While the DTR will allow for use of the maximum 1.55v, the voltage remains locked at a maximum of 1.45v for the mobile 1.4v CPUs.
- (b) nForce3-250; nForce3-250GB
- Asus K8N-E [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm; Tested with Athlon 64 DTR 1.5v][/b] - will boot with the shipping BIOS and runs smooth. Overclocking however seems to be an issue with the shipping BIOS. Upgrade to the 1004 BIOS and overclocking should be fine. Be advised that the backplate is *glued* on, which means it's tough to get off and you need to get it off. Using acetone or heating the adhesive up with a hairdryer should allow the backplate to be easily removed. Be careful and don't use sharp objects as they may damage the board.
Chaintech VNF3-250 Zenith Value Edition [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm, LDT; Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.4v][/b] - will NOT boot with shipping BIOS. What that means is that you have to get *another* DESKTOP CPU and flash to the 2004/7/29 BIOS found here:
http://www.chaintechusa.com/tw...?DCSNo=4&PISNo=276
Then swap out the desktop with the mobile chip. At that point the motherboard will boot but the CPU will lock down to a 4x multiplier (800Mhz) To correct this one needs to go into the Frequency/Voltage control menu in the BIOS and enable voltage adjustment and MANUALLY select the proper voltage for the chip. Then, in the same menu select the FID control and manually select the proper multiplier for the chip. Reboot and the problem should be solved.
DFI LANParty UT nF3-250Gb [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm, LDT; Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.4v][/b] - will work with shipping BIOS although there are reboot issues in that only once every 3-5 boots will the motherboard boot up properly. The issue seems to stem from the low voltage applied to the DTR upon boot. This hacked BIOS seems to fix the issue:
http://oskarwu.myweb.hinet.net.../BETABIOS/N32LD914.zip
Epox 8KDA3+ [AGP/PCI Lock, VCore via vmod, VDimm, LDT; Tested with Athlon 64 DTR 1.5v] - will NOT boot with shipping BIOS. What that means is that you have to get *another* DESKTOP CPU and flash to the new 9/13/04 BIOS. Then, with the desktop CPU still in the mobo you need to enter the BIOS and set the multiplier to 4x. At that point switch out the desktop CPU with the DTR and boot up. The system will boot up to 800mhz at 1.1v. From there enter the BIOS and adjust voltage to 1.55v and then adjust FID according to your CPU's default speed and you should be set.
MSI K8N Neo Platinum [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm, LDT; Tested with Athlon 64 Mobile 1.4v][/b] The board has some SERIOUS quality issues (there are too many problems to list but users are seeing everything from stability issues at stock, inability to get voltage to stay above 1.45v, only parttime working RAM divisors, flakey AGP/PCI locks, to multiplier and voltage settings that won't 'stick') Unfortunately, this is nothing new with MSI boards. What that means is that you may get a board that works fine but it is *much* more likely that you will get a board that is a big POS which will cause you to waste endless hours pulling out your hair trying (and failing) to get the board to work correctly. Until further notice, this motherboard is NOT a good choice to use with mobiles (or any other CPU for that matter.) The motherboard will boot with the shipping BIOS but the CPU will lock down to a 4x multiplier (800Mhz) To correct this one needs to update to the BETA bios 1.52 Please take note that the backplate is *glued* on, which means it's tough to get off and you need to get it off. Using acetone or heating the adhesive up with a hairdryer should allow the backplate to be easily removed. Be careful and don't use sharp objects as they may damage the board.
Soltek SL-K8AN2E-GR [AGP/PCI Lock, HTT Adjust, VCore, VDimm, LDT; Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.2v][/b] Any settings above 250 HTT will not take effect, even with the performance BIOS. However, it seems that with clockgen such settings do take effect. Otherwise, no major issues to report.
(c) nForce3-150- AOpen AK89 Max [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm, LDT; Tested with Athlon 64 Mobile 1.4v, Athlon 64 Mobile 1.2v][/b] - the 1.4v mobile will boot. However, the 1.2v mobile will NOT boot with shipping BIOS. What that means is that you have to get *another* DESKTOP CPU and flash to the 1.07a BIOS. Then swap out the desktop with the mobile chip. At that point, with both CPU types, the motherboard will boot but the CPU will lock down to a 4x multiplier (800Mhz) and reduced voltage. To correct this one needs to go into the BIOS and enable voltage adjustment and MANUALLY select the proper voltage for the chip. Then, select the FID control and manually select the proper multiplier for the chip. Reboot and the problem should be solved. One reported quirk with the combination involves the HTT resetting after the computer is turned off and then cold booted; it does not appear to be an issue when the system is simply restarted.
- Gigabyte GA-K8N Pro [AGP/PCI Lock, VCore, VDimm, LDT; Tested with Athlon 64 DTR 1.5v][/b] - will boot with shipping BIOS. However, HTT adjust is not available in the BIOS, but rather must be selected in Windows using clockgen. Also, no multiplier selection is available. One reported quirk is that voltages above 1.5v don't get saved properly in the BIOS, thus the system cannot be restarted. Rather, a full power off and then reboot is needed at which point the user must reapply the voltage selection.
(d) VIA K8T800/8237- Asus K8V Deluxe [NO AGP/PCI Lock, HTT Adjust, VCore, VDimm; Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.4v] - works fine out of the box. Correct speed and multiplier automatically selected by shipping and latest BIOS.
- MSI K8T Neo-FIS2R [NO AGP/PCI Lock, HTT Adjust, VCore, VDimm; Tested with Athlon 64 DTR 1.5v] - will not boot initially; user must clear CMOS. System will then boot up with CPU voltage at 1.1v and unidentified speed. User must then go into the BIOS and set CPU voltage to the proper 1.5v and the correct speed is then recognized by the BIOS upon reboot. Must do a clean install of Windows after CPU is used.
- Asus K8N-E [AGP/PCI Lock, FID 4x-Max, HTT Adjust, VCore, VDimm; Tested with Athlon 64 DTR 1.5v][/b] - will boot with the shipping BIOS and runs smooth. Overclocking however seems to be an issue with the shipping BIOS. Upgrade to the 1004 BIOS and overclocking should be fine. Be advised that the backplate is *glued* on, which means it's tough to get off and you need to get it off. Using acetone or heating the adhesive up with a hairdryer should allow the backplate to be easily removed. Be careful and don't use sharp objects as they may damage the board.
(8) Do any Micro ATX motherboards with mobiles?
- MSI K8TM-ILSR [Tested with Athlon 64 Mobile 1.4v] - a user claims to have this combination running. Upon booting the CPU will lock down to a 4x multiplier for a speed of 800mhz. However, using ClockGen and CPUID the proper multiplier and voltage can be selected for a perfectly working mobile Athlon 64 setup.
(9) Do any SFF Socket 754 systems work with mobiles?
- Shuttle SN85G4 V2 [Tested with Athlon 64 DTR 1.5v, Athlon 64 Mobile 1.4v] - will NOT boot with shipping BIOS. What that means is that you have to get *another* DESKTOP CPU and flash to the latest BIOS which includes mobile support. The SFF system likely also features an AGP/PCI lock as this setup has achieved a reported 270 HTT.
- Soltek EQ3801 [Tested with Athlon 64 Mobile 1.4v] - a user claims to have this combination running with a nice healthy overclock to boot. As of now, no other details are known and no other users have reported attempting the combination. Of concern however is proper contact of the heatsink with the mobile CPU.