Do 2 server CPUs of lower performance equal the performance of 1 desktop CPU twice as powerful?

ajthemacboy

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I didn't really know how to word the title. Here's what I'm wondering.

I'm looking to buy a very powerful rackmount server for a gaming server. Here's an example:

http://www.ebay.com/itm/Dell-PowerEdge-2950-III-Server-2x3-0GHz-E5450-Quad-Core-32GB-PERC6i-2-Trays-/171310202733?pt=COMP_EN_Servers&hash=item27e2e23f6d

According to CPUBoss:

http://cpuboss.com/cpus/Intel-Xeon-E5450-vs-Intel-Core-i7-4770K

An i7 4770k processor has 9.3 point performance score, and the E5450 has a 7.5. Since the rackmount server has 2 E5450s, will it have equal performance to the 4770k?

The E5450 has a lot more CPU cache, but the i7 has a 22nm architecture vs a 45nm architecture. I'm sure the i7 is probably better than 2 e5450s, but by how much?
 
Solution


Older architectures had poor horizontal scaling. Installing more CPUs usually created a nasty bottleneck somewhere. Two CPUs was fine, but four or more...
Desktop processors and Server processors are meant for completely tasks. Its hard to explain but for a server, get a server processor, for a desktop, get a desktop processor. and i7 cpu will not be a replacement for any Xeon processor that isn't ancient.
 
It comes down to the motherboard(s).

I suspect even an 'ancient' s771 2P server has some serious through-put as compared to a modern 'desktop' motherboard, with the added advantage of ECC RAMs.

The disadvantage is no upgrade path and power consumption.

edit: And, don't use CPU Boss as a comparison tool ... for pretty much anything.


 


From the perspective of a multi-process service architecture the dual E5450s will slightly edge out the i7-4770k.

From the perspective of a synchronous multi-threaded real-time application architecture the i7-4770k will significantly edge out the dual E5450s.

If you're looking to invest in a game-server machine that rackmount is not a bad choice. However, be mindful that rackmount servers are really noisy (I have tons of them). If you're colocating it, there are better options available now that Nehalem based servers are becoming available as end-of-life products.
 
Pinhedd, Can you elaborate on some better options?

I have a broken Proliant DL380 G3 right now and it is extremely loud, but I thought the newer PowerEdges might be quieter. Noise is a concern, though I don't mind a little whitenoise. (Note: The g3 is not a little white noise. I believe it may have caused hearing damage during the time I was messing with it.)

Wisecracker, would https://www.cpubenchmark.net/ be a better comparison site?
 


I have four HP ProLiant servers, two DL360 G2s and two DL580 G3s so I know exactly how loud they are 😀

If you're running this in a home setting you're not going to find a quiet rackmount and should look for a tower solution instead. Rackmounts need to pull air from the front to the back while moving it across several heat sinks, they're designed to be loud.

I have another rackmount colocated in a datacenter in Chicago for $65 a month. I'm considering replacing it with either a Dell Poweredge 900, DL580 G5, or waiting a bit until Nehalem based servers enter EOL
 
Oh, I just had an idea. Would keeping the server in a closet make the server quiet enough not to be distracting/annoying?

The closet has doors with 'fins' in it, which could be good for keeping it cool but bad for keeping it quiet, but probably still enough to quiet substantially.
 


If in a standard closet, you will soon have a very warm closet. Just like a PC case, you also have to extract the hot air.
And it will still probably be noisy. Rackmount servers are very short top to bottom. Limiting the size of the fan(s). To move enough air, you have several small fans, all spinning really fast. Fast = noise.
 
Ok, then what should I do? My budget is around $300 max, I really don't want to spend that much on this. I'd prefer it at $200 if possible.

I hear that building custom server PCs is really great, but it doesn't sound like I can build a good server for $200.

I also read online, here: http://www.poweradmin.com/blog/dell-poweredge-2950-server-quieting-the-loud-fans/, that you can quiet the fans of the 2950 I was looking at on ebay with a resister. How safe is this? Is this done often?
 


Nah, they're just newer native-quad/native-hex core CPUs which use an integrated memory controller.

There are several drawbacks to Core-2 based servers.

First, all Core-2 based CPUs are native dual-core devices. Four (Core-2 Quad on the consumer market), Six, and Eight core variants are actually constructed by gluing two, three, or four CPU dies together inside of the CPU package. Access to the platform is accomplished by multiplexing access to the front-side-bus. Logically, there's not much difference between a computer that uses a pair of dual-core Core-2 microprocessors (two sockets, one in each) and a computer that uses a single quad-core Core-2 microprocessor (one socket, but two dies contained within). Scale this to say, four sockets with three dies each for a total of 24 cores and the FSB needs to be split 12 ways (although some platforms contain dual-FSB for concurrent access). The end result is the potential for a severe memory bottleneck.

Second, most Core-2 based servers use the Intel X5000 chipset. This chipset uses DDR2-FBDIMMs which are a very particular type of memory module that are not compatible with the DDR2-DIMMs used in desktops of the same era. FBDIMMs allow for tons of memory to be installed without issue (128GiB servers are readily available on Ebay), but since there's still only two memory channels the total throughput leaves much to be desired. 17GiB/s is not a lot of memory bandwidth to share across up to four sockets.

Nehalem (and newer) based CPUs have a memory controller on each CPU and use the newer point-to-point (unshared) QPI bus to communicate with each other. Depending on the particular architecture, each CPU has two, three, or four memory channels of its own so this improves horizontal scaling.

If you're just looking to run a couple of game servers, a brand new Haswell based i7-4770k will do you well. It will be quiet enough to run in a home setting.
 
I agree; I have an i7 4770hq laptop with awesome performance, and it's not even an 4770k! Unfortunately I don't have that big of a budget. (See my last post.)

I think what you're saying is that it's better to have a single CPU in a server for better memory bandwidth, correct? I may have gotten that reversed. Or does this only apply with 2+ sockets in older architectures?

Next question: is it worth the money to buy a ddr3 supported server? Yesterday I read that 8GB ddr2 ram sticks are expensive, but looking them up they are only around $60. Is it worth the money to spend more?
 


Older architectures had poor horizontal scaling. Installing more CPUs usually created a nasty bottleneck somewhere. Two CPUs was fine, but four or more could be problematic as they had to go through the same chipset to access the platform's memory.
Newer architectures move that component onto the CPUs themselves, which greatly reduces that bottleneck and as a result four and eight socket systems work much better. Peripherals and platform components (such as the storage controllers) are connected to either the remainder of the chipset (which is connected to the first CPU) or directly to one of the CPUs via PCIe. It's pretty neat.

The case where it's really nice to have one CPU is synchronization-heavy real time tasks, such as multi-threaded gaming.

Multi-socket servers are excellent for running a large number of services at once. For example, a two-socket server may have a web server, email server and spam filtering, several databases, a couple of application servers, a DNS server, and a ton of other things all running at once. Since none of these processes need to run in lock-step with eachother there's minimal synchronization between them; as soon as synchronization is introduced (such as a process which spawns a large number of kernel threads that share memory) a lot of tiny performance issues creep up. Good software developers know how to work around this, but many just don't bother.

As for DDR2 vs DDR3...

DDR2 DIMMs can be expensive but DDR2-FBDIMMs are dirt cheap. A 24GiB kit of PC2-5300 FBDIMMs is around $70 and quad-socket servers with 128GiB of PC2-5300 FBDIMMs (two channels) are in the $800 range right now
 
Solution
Ok, now it comes down to picking one to look at.

I've been looking on ebay. Here's one of my searches:

http://www.ebay.com/sch/Enterprise-Networking-Servers-/175698/i.html?_from=R40&_nkw=16gb+server&_dcat=11211&Form%2520Factor=Rack%2520Mount&rt=nc

Do you see any that stand out as good?

I was looking at this one:

http://www.ebay.com/itm/Dell-PowerEdge-CS24-SC-2X-Xeon-X5460-3-16GHz-16GB-RAM-4X-73GB-HDD-/221510187599?pt=COMP_EN_Servers&hash=item3393093a4f

According to this video, it's easy to quiet by removing 2 fans:

https://www.youtube.com/watch?v=Q7O77hhh_Fc

However it gets loud and up to 81 degrees F with prime95 running. I don't plan on running extremely intensive processes like that, however.

Here comes a problem though. The game server software for the servers I might run (tf2, minecraft, garry's mod) probably havn't been coded to run on 2 CPUs. Minecraft is based on java, do you know if it has been programmed to run alongside on 2 CPUs?

Do you know if the server above has FBDIMMs? I can't find a datasheet for it. I'd probably like to upgrade RAM some day.

There is also a basement where I live. I could put the server down there and nobody would notice. The only problem would be running an ethernet cable to it, which wouldn't be too big of a deal I don't think. It's big and the air is cool, perfect for a server. It also has a dehumidifier so components won't be damaged.
 


Do not remove fans from a rackmount server, ever. They are installed in a redundant fashion such that if one or two fail, the server will be adequately cooled until they are replaced. If you were to remove a couple of fans to quiet it down, you would be removing that redundancy. Furthermore, the high-pitched drone of the server will still be audible throughout your house.

What you should do is look for tower servers as these use much quieter fans.
 
The house is two stories; the lower is a finished basement with a long workshop area. The furthest part is right below the router. Is there a way to make it less high pitched and just 'loud?' Maybe something to dampen it?

I looked on ebay for some tower servers. I found this:

http://www.ebay.com/itm/HP-xw6600-WORKSTATION-3-00GHz-QUAD-CORE-16GB-RAM-250GB-HDD-NO-OS-/171444791124?pt=COMP_EN_Servers&hash=item27eae7e754

Which according to the datasheet has an e5450. Would this be good enough to run a game server?

This has a e3-1245 but it's out of my pricerange.

http://www.ebay.com/itm/SERVER-ThinkStation-E31-3-4-Xeon-E3-1245-Quad-16GB-RAM-500GB-SATA-Win-7-Pro-/161526115872?pt=COMP_EN_Servers&hash=item259bb4ee20

If it lowers in price or I can find something similar that's probably what I'll get.
 


That ThinkStation is the much better offer
 
I just remembered something else. If I want to run a Minecraft server, which runs on Java, can only use a single core of a single CPU (as far as I know.) Minecraft is not programmed to use multiple threads/cores.

1. If this is the case, would getting a single CPU server be better than a multi CPU server?

2. If this is the case, would getting a server with a single core be better than getting one with multiple cores?
 


Minecraft is mostly single threaded, but there are a number of lighter threads handling things such as file IO, asynchronous networking, etc... I haven't touched it in a while but if you're looking to only run a single Minecraft server, a single-socket system would probably be fine.