Refurbished vs. New: Dell PowerEdge Servers
By Nick Sansevero, Product Manager, 2NDGEAR
We’re moving from the desktop experience and taking you to the data center to explore refurbished vs. new on Dell PowerEdge servers. In this blog’s match-up, we’ll be taking a look at how a refurbished Dell PowerEdge R720xd compares to a new Dell PowerEdge R730xd.
When it comes to refurbished vs. new on servers, the first question we always get is OS support. Under Windows Server 2016, both the R720xd and R730xd are certified by Dell. The R730xd adds support for TPM 2.0 while the R720xd does not.
For VMware users, the support is always defined by the processor. The R720xd supports the E5-2600 series Xeon’s CPUs both v1 and v2 which are supported under the latest versions of VMware (currently 6.5 U1) and the R730xd also supports the latest version. VMware just discontinued the 5600 series Xeons (this was the CPU platform for the 11th gen Dell servers) so the E5-2600 v1 would be next on the list. Since 6.5 U1 was released recently, the v1 CPUs likely have a support life of another two years. Fortunately, a simple CPU upgrade to the v2 platform will extend the life of your investment.
Performance
When it comes to performance, we’ll review and outline the differences between the R720xd and the R730xd in terms of compute and storage capabilities using benchmarking and rough calculations for throughput both in I/O and network capabilities. We’ll also look at Raid Adapter support as this has been a popular topic for vSAN implementations.
From a Processor Perspective
Starting with the refurbished R720xd, the Dual Intel Xeon E5-2680 v1 8C Passmark benchmark is 18,290. The Passmark CPU benchmark result is the CPU performance performing raw activities such as floating-point calculations, which is a series of mathematical calculations and the speed at which the CPU can perform them at. 2NDGEAR sells the E5-2680 v1 CPU at $165 in most of our builds, including the R720xd.
If the R720xd is equipped with a Dual E5-2680 v2 10C, the benchmark score jumps to 22,754, which represents a 19% performance increase over the v1 variant. The current price for the E5-2680 v2 is $235 in our server builds that support it which represents a 29% price increase over the E5-2680 v1.
For the R730xd, using the E5-2680 v4, the Passmark score closely resembles the E5-2680 v1 at 19,946. You do gain additional mileage in the form of CPU cores as this CPU is a 14C CPU.
Another way to look at CPUs, especially in a virtual environment, is to look at Total Compute which you can do by multiplying the clock speed with the physical core count. This is an easy way to look at your current total compute and roughly determine if displacing your ten servers with four will cause any bottlenecks in terms of compute. Here is a quick chart outlining the differences between the E5-2680 v1, E5-2680 v2, and E5-2680 v4:
| Processor Model | Core Count | Clock Speed | Total Compute | % Gain | Price |
|---|---|---|---|---|---|
| E5-2680 v1 | 8 | 2.7GHz | 21.6GHz | 0% | $165.00 |
| E5-2680 v2 | 10 | 2.8GHz | 28.0GHz | + 22% | $235.00 |
| E5-2680 v4 | 14 | 2.4GHz | 33.6GHz | + 16% | $1,574.78 |
Is the massive jump in cost from v2 to v4 as well as the additional software costs worth the performance increase? We’ll leave that up to you to decide.
From a Memory Perspective
Memory support and CPU go hand in hand. The E5-2680 v1 has a maximum support of 1600MHz DDR3. Since the majority of our 2NDGEAR builds using this CPU go out with 1333MHz, we’ll use that in the upcoming calculations. The E5-2680 v2 supports a maximum of DDR3 1866MHz but since most of our E5-2680 v2 builds go out with 1600MHz, we’ll use that for reference. Lastly, the E5-2680 v4 supports DDR4 2400MHz modules and since you are buying new on this model, chances are that will be what you will select – so we will use that in our math.
Another piece to think about with servers are the channels the server model supports. The R730xd is superior with 3 memory channels to the processor as the R720xd only has 2 per CPU. This will allow for more throughput between memory and the processor on any pending functions the CPU needs to perform.
Here is a chart to reference memory throughput across the R720xd and the R730xd:
| Processor Model | Memory Type | Memory Density | Memory Speed | Server Model / DIMM Slots | Memory Channels Per CPU | Max GHz | Cost Per DIMM |
|---|---|---|---|---|---|---|---|
| E5-2680 v1 | DDR3 | 16G | 1333MHz | R720XD / 24 | 2 | 2,666.00 | $75.00 |
| E5-2680 v2 | DDR3 | 16G | 1600MHz | R720XD / 24 | 2 | 3,200.00 | $95.00 |
| E5-2680 v4 | DDR4 | 16G | 2400MHz | R730XD / 24 | 3 | 7,200.00 | $325.00 |
To visualize the throughput in the Max GHz column, you can compare this information with PCI-E and the data rates that are pushed through that interface.
Since PCI-E 3.0 has a base clock speed of 8.0GHz, you can compare this with the memory throughput numbers of the R730xd. PCI-E 2.0 has a base clock speed of 5.0GHz so this can be used (roughly) as a comparison for the R720xd. Here is a chart to help you see the differences:
| Interface Type | Clock Speed | Data Rate | Bandwidth |
|---|---|---|---|
| PCI-E 2.0 | 5.0GHz | 500MB/s | 16GB/s |
| PCI-E 3.0 | 8.0GHz | 1000/MB/s | 32GB/s |
From a memory perspective, the R730xd is vastly better if you need that kind of throughput but unfortunately, that performance comes at a significant cost. At almost 4x the cost, you can get double the memory performance.
From a Storage Perspective
The R720xd backplane supports 6GB/s hard disk drives as well as SSDs. 12GB/s drives are backwards compatible with the slower backplane but it would not make sense to buy 12GB/s drives if you will only use 6GB/s. The R730xd supports 12GB/s but will you use this sort of bandwidth? Let’s do some math:
Most enterprise SSDs come in around 8,000-10,000 IOPS – and in a server, you will want enterprise-grade SSDs. The fastest SSD currently (whether enterprise grade or consumer) is the OCZ Vertex 4 which will support up to 120,000 IOPS per disk. Since the OCZ Vertex 4 comes in at 560MB/s in an average sequential read test and 510MB/s in an average sequential write, it would take 10 of these drives to bottleneck a 6GB/s backplane.
This would mean that a 6GB/s backplane can support up to 1.2 million IOPS before you crash the Gibson. To put this into perspective, a Nimble Storage AF9000 (which is an all flash SAN using 16Gbit/s Fiber) will support 1.4 million IOPS.
What does this mean? In my opinion, the 12GB/s backplane support, as well as drives or SSDs themselves, is a gimmick.
From a Raid Perspective
We have customers who were concerned about using an R720xd for vSAN implementations primarily because VMware does not certify support for the older Perc cards. Fortunately, we have successfully tested X4TTX H730P Perc adapter cards in an R720xd. This card is a PCI-E enabled card and a conversion cable can be used so the SFF-8087 connector on the R720xd aligns with the SFF-8463 connector on the H730P. No limitations as far as raid functionality goes. Also for vSAN, a pass-through can be used such as an LSI MegaRaid without any limitations if this is preferred.
Thank you for taking the time to read this blog. I want to leave you with comparison builds on the R720xd vs. the R730xd, for both density as well as performance. Hopefully this brings together the different perspectives on comparisons and helps you determine whether the preference is either refurbished servers or new servers.
Density Build
Refurbished Dell PowerEdge R720xd 2U – 12 Bay 3.5”
- 2 x Intel Xeon 10C E5-2680v2 2.7GHz CPUs
- 384GB (24x16G) DDR3 Registered DIMMs
- 12 x 3TB NL-SAS 7.2K RPM 3.5” HDD in Dell Trays
- 2 x 600G MLC SSD in Dell 2.5” Trays
- FlexBay 2 x 2.5” Rear Drive Kit
- Dell Perc H710P w/ 1G Cache Raid Adapter
- Dell IDRAC Express Management
- Integrated Quad Port 1G NIC
- Redundant 750w Power Supplies
- Dell R720 Bezel
- Dell R720XD 4 Post Square Hole Rail Kit
- 3 Year 2NDGEAR Hardware Warranty
- Includes Free Shipping
Price: $6,585.03
New Dell PowerEdge R730XD 2U – 12 Bay 3.5”
- 2 x Intel Xeon 14C E5-2680v4 2.4GHz CPUs
- 384GB (24x16G) DDR4 Registered DIMMs
- 12 x 2TB NL-SAS 7.2K RPM 3.5” HDD in Dell Trays
- 2 x 200G MLC SSD in Dell 2.5” Trays
- FlexBay 2 x 2.5” Rear Drive Kit
- Dell Perc H730 w/ 1G Cache Raid Adapter
- Dell IDRAC Express Management
- Integrated Quad Port 1G NIC
- Redundant 495w Power Supplies
- Dell R730 Bezel + Dell R730 4 Post Square Hole Rail Kit
- Dell 3 Year Standard Warranty
Price: $18,387.66
Performance Build
Dell PowerEdge R720XD 2U – 24 Bay 2.5”
- 2 x Intel Xeon 10C E5-2680v2 2.7GHz CPUs
- 384GB (24x16G) DDR3 Registered DIMMs
- 24 x 900GB SAS 10K RPM 2.5” HDD in Dell Trays
- 2 x 600G MLC SSD in Dell 2.5” Trays
- FlexBay 2 x 2.5” Rear Drive Kit
- Dell Perc H710P w/ 1G Cache Raid Adapter
- Dell IDRAC Express Management
- Integrated Quad Port 1G NIC
- Redundant 750w Power Supplies
- Dell R720 Bezel
- Dell R720XD 4 Post Square Hole Rail Kit
- 3 Year 2NDGear Hardware Warranty
- Includes Free Shipping
Price:$11,583.33
Dell PowerEdge R730XD 2U – 24 Bay 2.5”
- 2 x Intel Xeon 14C E5-2680v4 2.4GHz CPUs
- 384GB (24x16G) DDR4 Registered DIMMs
- 24 x 600GB SAS 10K RPM 2.5” HDD in Dell Trays
- 2 x 200G MLC SSD in Dell 2.5” Trays
- FlexBay 2 x 2.5” Rear Drive Kit
- Dell Perc H730 w/ 1G Cache Raid Adapter
- Dell IDRAC Express Management
- Integrated Quad Port 1G NIC
- Redundant 495w Power Supplies
- Dell R730 Bezel
- Dell R730 4 Post Square Hole Rail Kit
- Dell 3 Year Standard Warranty
- Does Not Include Shipping
Price: $21,656.47
Have questions or need assistance in building out your next servers. Leave a comment below or email us at info@2NDGEAR.com. Also be sure to check out our offering of refurbished and recertified servers, including the Dell PowerEdge R720xd, on our online store.
Sources:
https://ark.intel.com
http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/Documents/Dell-PowerEdge-R730-and-R730xd-Technical-Guide-v1-7.pdf
http://www.karma-group.ru/upload/iblock/2a2/dell-poweredge-r720-r720xd-technical-guide.DFB1D87F0E0C4C1EB70D884290B5F68C.pdf
https://en.wikipedia.org/wiki/IOPS
https://www.trentonsystems.com/industry-applications/pci-express-interface
http://www.makeuseof.com/tag/pc-benchmark-tests-what-are-they-and-do-they-actually-matter/
https://www.cpubenchmark.net
https://www.vmware.com/resources/compatibility/search.php
http://en.community.dell.com/techcenter/b/techcenter/archive/2016/11/10/dell-poweredge-servers-certified-for-windows-server-2016
