Both the Dell PowerEdge R720 and the Dell PowerEdge R720XD are 2U rackmount servers. These rackmount servers have the capability of running Intel Xeon E5-2600 series and Intel Xeon E5-2600v2 processors *You must have BIOS revision 2.0.19 update or later installed to use the v2 processors. These rackmount servers also offer twenty-four DDR3 slots for RDIMMS, LRDIMMs, and UDIMMs.
The R720XD weighs in at just a few pounds more than the R720 due to its significant increase in Hard Drive Bays. The R720XD has a few different options for hard drive bays and can hold a staggering twenty-four two and a half inch hard drives or twelve three and a half inch hard drives while the R720 can only hold a maximum of sixteen two and a half inch or alternatively eight three and a half inch hard drives.
For v1 processors, BIOS revision 1.4.8 upped the maximum frequency supported to 1600MHz for both RDIMMs and UDIMMs when using one or two channels at either 1.5V or 1.35V. BIOS update 1.4.8 also upped the maximum default frequency to 1333MHz on a three DIMMs per channel layout for both RDIMMs and LRDIMMs.
While moving up the BIOS update chain, if you are using BIOS update 2.0.19 you will be able to use the Intel Xeon E5-2600 v2 processors and also the LRDIMM will support 64GB because in a patch released before the v2 processors were even compatible they released an update (BIOS update 2.1.2) that made that possible. In a later update (BIOS update 2.4.3) LRDIMMs at two DIMMs per channel will have its max supported memory speed upped to 1866MT/s for 32GB.
What to look for when checking compatibility of a processor
Picking out a processor can be a difficult task. There are many different aspects you need to look at in order to make sure a specific processor will work with your system. Sometimes the documentation is incomplete or you can't find it. Sometimes there is just some weird combination of factors that make things not work and sometimes the information straight from the manufacturer is simply incorrect. In this guide, I am going to explain to you how to sift through the information so that you can determine whether or not a processor will work in your system. In the end, it is very simple. There are only really 4 factors for most modern systems, even less if you are using desktop parts. The factors are socket type, processor generation, motherboard chipset and BIOS revision (and memory type if you are on a server).
This, in the past, was the simplest of aspects to look at when determining a processor for a system because it is essentially just like when you played with blocks when you were a kid and needed to put the correct block in the same hole. This has been complicated in recent years because both Intel and AMD have decided to use very similar socket types across a few generations of processors and only swap out one or two pins or upgrade a chipset without changing the socket. This means that nowadays a processor may still fit in the socket but is still not compatible. This is still the simplest way to quickly disqualify many processors from your potential hunt. Simply put, if a processor has a different socket type from your motherboard then it will not work for you( excluding rare cases like where you can use an LGA775 to LGA771 adapter). There are two quick and easy ways to check the socket type of your motherboard. The first is to go directly to the manufacturer and go to their support area and search up your motherboard or desktop. If you are unsure of what model you have you can use our tool to look up your motherboard or desktop model and then look at the manufacturer's website with that information
Another option is to find the socket type directly by downloading a tool like CPU-Z and letting that do a quick scan of your system.
Once you have found which socket your motherboard has you can start looking at potential processors. One option, if your motherboard uses an Intel processor, is to check the Intel ARK. This website is Intel's official knowledge base which holds just about any processor information you could possibly want. You can do a simple search in the top right for your socket and it will tell you all of the processors that will fit in your socket. This does not guarantee compatibility with your specific system, but it is a start.
If you do not have an AMD motherboard or you could not find any results for your Intel motherboard on the ARK then you can also use a similar tool found at CPU-World. Just find the Socket Type option and then select "contains" and then type in your socket type. After this initial search, you may need to do another search by selecting from a list it gives to you to narrow down the results to your specific socket, but after you do that it should give you a list of potential matches exactly like the Intel ARK. Now you have a list of potential candidates so we can move along to processor generation and motherboard chipset.
Processor Series and Motherboard Chipset
These two next factors go hand-in-hand because generally a new motherboard chipset is released with each series of processors and a processor released with that chipset will be compatible in almost all cases. In the past, it was easy to determine the processor compatibility by looking at the first number of a part number, but recently this has become an unreliable method. For example, relatively recently, Intel released the 4770k and the 4930k at the same time so you would think that they would both work in the same motherboards, but, in fact, they do not even use the same sockets and are incompatible. For a 4930k you need an X79 motherboard and for a 4770k you need a Z97 motherboard. This is why it is dangerous to just look at the leading number. It is best to look at the processor series. In the previous example, you could look up the 4770k and find it was a Haswell processor and then with a search on the Intel ARK you could find a list of the compatible chipsets. To find out which chipset your motherboard uses you can look at the support site from the manufacturer of your desktop again or use CPU-Z again. Many times you do not even need to use these resources if you already know the name of your motherboard though because often the chipset is in the motherboard's name. For example, ASUS Z170-A LGA 1151 Intel Z170 HDMI SATA 6Gb/s USB 3.1 USB 3.0 ATX Intel Motherboard. This tells you in the name that it is a Z170 motherboard and it has an LGA 1151 Socket.
The final factor to look at is the BIOS revision. This is a commonly overlooked factor but can often be a huge frustration point that many people forget about or did not know about in the first place. To simply explain what the BIOS is for those who do not know, it is basically the hardware level settings for everything plugged into your motherboard. In order to run the processor you want, it must have a new enough processor microcode. The microcode is basically the directions for a list of processors and how to run them. If the BIOS does not have the microcode for your processor then it will not boot up because it doesn't have the proper instructions to initiate the processor. Luckily for you, the BIOS is updateable and if a processor comes out after a motherboard is released you can put a newer BIOS on your motherboard and then it will be able to accommodate the new processor. One thing to really emphasize though is that you must update the BIOS before installing the new processor. Some manufacturers now have a tool so that you may update the BIOS via USB without a processor installed but in many cases that may not be possible.
Now that you know all about what the BIOS is and what you can do with it I can talk to you about what you need to look at to confirm compatibility. The first thing to do is to simply look at your motherboard or desktop manufacturer's website. Typically this information will be under support and then maybe downloads and then you will find various BIOS versions there. Some manufacturers will simply list out which processors are compatible and which aren't but for some you will need to delve into their documentation a little bit further. The document name I typically look for is Release Notes somewhere near the BIOS version. In these documents, you can find if there is a version of the BIOS which included an update to the microcode or added compatibility for a certain series of processors. If you find that the processor you want to use was added on by a BIOS update then you need to check for your BIOS revision and make sure it is newer than the required version to run the processor you want. You can find this in CPU-Z under the mainboard tab.
If your BIOS revision is not new enough then you will need to update it before you can use the new processor. You can either find the most recent version off of the manufacturer's website or you may use a tool like BIOS Agent Plus to find the most recent version for you and help you install it. It is very important to make sure that you follow any directions given to you very closely when dealing with the BIOS because you can easily brick your motherboard if you turn off the power when updating or if you update with the wrong version.
TDP( Total Design Power)
TDP is another thing that used to be an important consideration when looking at processors and motherboard compatibility but it has fallen by the waist side as systems have become more efficient and developed the standards to deliver adequate power. I figured it was worth to add in any way for those who may be using older systems. To explain for those who do not know what TDP is, it is basically the total wattage that the CPU will consume and then convert to heat. This is a particularly important consideration on all of the AMD processors because if you look at the highest end processors they have the FX-9590 has a TDP of 220W. This is a gargantuan number in comparison to most current processors and many motherboards likely cannot put that much wattage through their socket without melting their voltage regulators or frying themselves. For reference, 220W is likely more power than your entire system draws if you are on a modern system and do not have a high-end graphics card installed. If you have an AM2, AM2+, AM3, or AM3+ and are looking for compatible parts it is probably wise to also consider the TDP and see if there is any documentation along with your system that says specifically whether it can handle a 135W processors or just a 90W processor and you may also even want to look to see if your power supply can provide ample wattage. I have seen plenty of pre-built systems that have power supplies rated for 225 watts or less and if you plug an FX-9590 into one of those you would really be playing with fire.
To summarize, the first thing you should look at when looking for compatible processors is the socket type. If you do not have the correct socket type then the processor will likely not fit or the pins will not match up. After you determine that it is the correct socket you should look at the CPU series and compare it to the chipset series. There are plenty of resources online to make sure that your motherboard has a chipset that will likely be compatible with the processor you are interested in. Check Wikipedia or the Intel Ark and they will guide you in the right direction. After that, you should look at the manufacturer's website and see if the processor is listed in their documentation anywhere and if it is, does it require a new BIOS revision to run. These are the basic steps that I run through whenever I am uncertain about the compatibility of a processor. If you have any further questions about compatibility or have something you would like to add to this guide, please leave a comment and I will try to address it as soon as I can.
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