View Full Version : Differences between Dual core and Dual processor.
physics_geek
12-10-2005, 08:46 AM
For example there are two systems one is dual core at 2.4GHz and other is just two 2.4Ghz single core CPU system. Which is faster?
softpain
12-10-2005, 09:41 AM
The one with the best optimize software...:)
For example there are two systems one is dual core at 2.4GHz and other is just two 2.4Ghz single core CPU system. Which is faster?
Basically the same for the same clockspeed.
If the DC system is a socket 939 system it will usually have faster RAM. That is usualy close to useless, but if there is a speedup the speedup will apply even to individual threads.
The dual-CPU system will often have NUMA memory banks, seperate memory for each CPU. With the current state of software, this is mostly useless, too, and doesn't bring you any improvements for one thread running anyway. Plus the memory will be ECC registered non-overclocked so you start lower.
None of the above really matters for normal applications.
However, the real killer is clocks.
The dual 940 system can be had up to 2.8 GHz stock speed, which you cannot get for dual-core chips. Even the FX-60 will only give you 2x 2.6 Ghz.
The dual-core 939 system on the other hand usually comes in boards that support overclocking well, so you might end up with 2.8 GHz, too.
For actual filesyem or database server usage the dual 940 system will always win because you need PCI-X to get decent speed SCSI RAID, 4-port GbE and similar items into the box. This is not available for 939 systems. The PCIe SCSI raid controllers so far are expensive and don't seem to work well at all.
Last but not least the 939 systems only support 4 GB of memory which just isn't enough for many uses (Battlefield 3 :)).
z-design
12-10-2005, 12:13 PM
Dual processor pros:
-Dual processors have 2 physical single core chips, therefore it will produce less heat than a dual core chip.
-You can update to quad core by buying 2 dual core 940 chips.
-Dual processors are for servers and therefore, they are more reliable and last a lot longer. They can have an uptime of more than 10-years without being turned off.
-You can have SCSI drives.
-With ECC ram, there is practically no chance of getting a bsod/ram instability.
-Scalable up to more than 4gb of ram.
-Can have higher clock speeds than dual cores. Currently, dual cores can have 2 cpus at only 2.4ghz, until the opteron 185, and fx-60. Right now, you can buy two opteron 254s at 2.8ghz.
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Dual processor cons:
-Need a big case, though with the exception of the iwill zmaxd2
-Two heatsinks, more fans = more noise
-ECC ram is slightly slower, but it has its benefits.
-Can't overclock as well, if you dont oc, it will last very long.
-Limited boards with SLI, but there are some.
-more expensive
physics_geek
12-10-2005, 08:11 PM
Thanks guys.
Dual processor pros:
-Dual processors have 2 physical single core chips, therefore it will produce less heat than a dual core chip.
Huh? Where'd you come up with the logic on that one? Yes, a single-core
will produce less heat than two cores, of course. But we're talking dual
processors here. Whether you have two cores across two seperate chips or
two cores within a chip, it's STILL two cores. Where the advantage comes in is in the ability for two physical entities to dissipate heat better due to more physical surface area. Aggregate heat in the system is another story, however.
Dual processor pros:
-Dual processors are for servers and therefore, they are more reliable and last a lot longer. They can have an uptime of more than 10-years without being turned off.
That's a bunch of bunk. No actual data. If anything having two of something increases the statistical MTBF. Now the ability of a second CPU to take over in case of failure of the first is implicitly there - but if you think a single CPU failing in a dual-CPU system will not bring the system down - you've got another thing coming. There is no implicit reliability advantage to having a dual-CPU system first a single-CPU system.
Dual processor pros:
-You can have SCSI drives.
Another huh? here. Has nothing to do with single or dual.
Dual processor pros:
-With ECC ram, there is practically no chance of getting a bsod/ram instability.
Like it's ever an actual issue even with non-ECC. ECC is for suckers.
Dual processor pros:
-Scalable up to more than 4gb of ram.
Nothing to do with single vs dual CPUs but everything to do with the CPU's addressing scheme (32 vs 64 vs 128-bit, etc.). Less than 1% of the people here will even utilize code which demands more than 4 GB in daily use.
Dual processor pros:
-Can have higher clock speeds than dual cores. Currently, dual cores can have 2 cpus at only 2.4ghz, until the opteron 185, and fx-60. Right now, you can buy two opteron 254s at 2.8ghz.
Nothing to do with single vs dual CPUs but everything to do with the design of the package. Currently there's a heat barrier. Two physical CPUs help against this but as mentioned before, aggregate heat is still an issue.
It sounds like you own, or desire to own a dual-CPU system.
ECC RAM becomes a big factor once you understand the damage a single flipped bit can do. And if you take into account how many bit you have with 2 or 4 GB of RAM. My reasoning is here: http://cracauer-forum.cons.org/forum/ecc.html
But you can get ECC for socket 939 and 754, too, you just have to live with an Asus board.
And keep in mind dual-core AMDs are two low-power cores (compared to the non-HE single cores).
Regarding SCSI, it is an unfortunate fact right now that there are no socket 939 board which allow you to plug in fast SCSI controllers, the only available PCIe controller seems to have issues. So you need PCI-X or onboard and that's not available for socket 939.