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.
RAM Type: DDR4 RDIMMs, LRDIMMs
Max Ram Capacity: RDIMMs: 768GB(32GB DIMMs), LRDIMMs: 3072GB (128GB DIMMs)
Processor Socket Count: 2
Compatible Processor Series: E5-2600 v3, v4 or E5-1600 v3, v4
Number of Ram Slots: 24
Hard Drive Bays: 18 3.5" drives or 32 2.5" drives
BIOS Notes: Revision 2.1.5 adds support for E5-2600 V4 and E5-1600 V4 processors
128GB LRDIMMs Supported with V4 processors and BIOS 2.1.5 and newer.
The Dell PowerEdge T630 is a Tower based server that has the ability to be converted into a rackmount server when a mounting bracket and rails are installed. It features a proprietary Dell motherboard which is run by an Intel C612 series chipset (Desktop Similar is the X99 Chipset). This allows for dual Haswell-EP (E5-2600 v3 series) processors or Broadwell (E5-2600 v4 series) processors (If BIOS revision 2.1.5 or newer is installed) and 24 slots for DDR4 RDIMMs or LRDIMMs
When running BIOS revision 2.1.5 or newer the maximum addressable memory for a single socket configuration is 1536GB with Quad or Octo Rank Load-Reduced DIMMs. With a dual processor configuration, this figure is doubled to 3072GB. This is using 24 of the recently released 128GB LRDIMMs. If using a revision older than 2.1.5 then the maximum addressable will be 768GB in a single socket configuration or 1536GB in a dual socket configuration. This is achieved using 24 64GB LRDIMMs. Of note, you cannot utilize 128GB DIMMs until the BIOS is updated and you may not use the memory slots assigned to a non-populated processor. To explain further, you cannot achieve the 768GB single processor maximum by using 24 32GB DIMMs because 12 of the slots are associated with the empty processor socket. The memory can operate at 2400MT/s in all configurations and ranks except for triple channel configurations. With RDIMMs the maximum then becomes 1866MT/s in triple channel and LRDIMMs can still operate at 2133MT/s in triple channel
There are many storage configurations for the Dell PowerEdge T630. One option is 32 2.5" drives without the flexbay or 18 2.5" with the flexbay. Another option is 18 3.5" drives without the flexbay or 8 with the flexbay. The flexbay is essentially a riser card that allows the install of PCIe SSD cards in the front or additional hard drives or solid state drives.
There are a few known issues with the T630 that have been addressed with BIOS updates. The most major being users experiencing the red screen of death (RSOD) when using the E5-2603 or E5-2609 processors and performing a reboot. This was remedied in BIOS revision 2.1.5 so if you are using this configuration it is highly recommended you upgrade.