EVGA Killer Xeno Pro: The Impact of Network Offloading
by Derek Wilson on July 3, 2009 4:20 AM EST- Posted in
- Networking
Final Words
The approach and design of the Killer Xeno Pro are more efficient than standard network cards. Bypassing the windows networking stack will reduce load on the operating system and the CPU. Bypassing the CPU and OS when sending and receiving audio using supported voice chat software is a cool thing as well. Built in hardware prioritization (QoS) and bandwidth throttling are also interesting features.
But the bottom line is that none of this makes a significant difference in the gaming experience on modern PCs when paired with current games, nor does it offer an advantage over alternatives.
The biggest advantage the Killer Xeno Pro showed was in it's ability to prioritize games over other applications. At the same time, this only works for the one PC that is doing both downloading and gaming. If there are other computers on the network at all, it would be much more cost effective to purchase a router that can handle QoS and bandwidth control on a per application (or per port) basis. Using a router to handle this means that I can download huge massive files on one PC and my wife can play Team Fortress 2 on another without experiencing problems.
I could even play a game on the computer that I'm downloading with in that case, but it remains our recommendation to simply not download in the background while playing a game. More than just networking is affected by downloading in the background, as the harddrive is constantly being hit and this can be a significant source of loading pauses and hitching in and of itself.
If you don't want to spend any money, most torrent and other downloading applications come with built in (or add on) bandwidth controls that can be employed to achieve the same end as hardware QoS. Hardware QoS and bandwidth control are nice features to have, but they are not worth $120.
The voice chat acceleration could be beneficial when gaming while chatting, but currently most applications are not supported. Teamspeak, Ventrillo, and Skype all need out of the box support at the very least. At best we would want all games with built in voice chat to support this as well, but that isn't likely unless and until the hardware becomes more popular. In addition to application support, voice chat doesn't take up a significant amount of CPU time and the most significant impact on latency is still going to be the network as a whole.
TCP/IP offload is a better way to do things, but the benefit to the gamer just isn't there. Network load just isn't high enough to really take advantage of the hardware in modern games. But it isn't like the potential benefit of an NPU can never be realized: it starts to matter in the server space where technology like this was originally targeted. Offloading the CPU of a heavily loaded database server can definitely leave more CPU time for processing tasks and can increase network responsiveness. This just isn't what the Killer Xeno Pro is targeted towards.
So, when you've already got an on-board network card, is the Killer Xeno Pro worth $120-$130 USD? When that money can be put into either CPU or graphics, the answer just has to be no. At the same price as a Radeon HD 4850, there is just no reason not to look toward upgrading older graphics solutions. If you've already got something on the level of the 4850, then that money should be saved for your next graphics hardware upgrade where it will still have a higher impact on performance and experience.
For professional gamers and those obsessed with twitch shooters, for the gamers running 1280x800 on a 30" panel with most of the settings turned down on the highest end hardware money can buy, for those who are always after whatever option might give them the slightest edge: the Killer Xeno Pro might be for you. But even then, this hardware is the icing on the cake rather than a core ingredient.
What the geek inside me really wants to see is more general access to the hardware. This is, after all, a PC on a PCIe card. If Bigfoot gave us deeper access to the hardware, we might find more (even if equally niche) uses for an extra PowerPC processor in our computers. Additionally, to satisfy our intellectual curiosity, we would like to get our hands on a couple more of these cards in order to do some LAN testing using combinations of standard and Killer network cards to see how overall network performance is changed (if at all) especially with respect to voice chat performance.
Beyond this, there is a caveat. Perhaps, as broadband becomes more pervasive, game developers might want to push networking. At some point in time, games may need the PCs they run on to handle a much larger volume of network traffic in order to function well. Right now, game developers are targeting current bandwidths using current commodity network hardware. Games can't be designed to require higher performance networking gear because consumers either don't have access to high speed internet or they don't have a network card that does TCP/IP offload (among other things).
At some point down the line, something like the Killer Xeno Pro might become a significant requirement. But right now, for the vast majority of gamers out there, our advice is to save your money.
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mindless1 - Saturday, July 4, 2009 - link
The thing is, even with a slower CPU and PCI bottleneck, the network processing still isn't a substantial % of processing by the CPU, and the traffic for gaming not bottlenecked by PCI bus.Even a lowly Celeron 500MHz isn't much of an issue if jumbo frames are used, though CPU still has to be seen as a bottleneck to the gaming itself.
has407 - Sunday, July 5, 2009 - link
Jumbo frames won't do squat in this case, and will likely cause worse problems. Even in well--managed and closed environment, expect very little gain unless you're using a very fast SAN, fast switches, and a network admin who knows what they're doing.Do the math: even for 1Gbe networks the efficiency gain for most apps using jumbo frames is noise. For 10Gbe you might notice it if you've got enough CPU and IO bandwidth; for the typical home network, it's not worth considering.
davecason - Saturday, July 4, 2009 - link
PCIe, not PCI.Theunis - Saturday, July 4, 2009 - link
I wonder if it would be possible to use this board with my Linux x86_64 machine. LOLWouldn't it be cool to run specific applications compiled for PPC, to run on this board? Does it come with it's own RAM?
ShawnD1 - Saturday, July 4, 2009 - link
If they're trying to market this thing as something to reduce CPU usage, it doesn't really make much sense to test it with the fastest processor you can find. Try it with a CPU that has no speed at all, maybe a celeron or sempron.Of course that's not a real world test, but are any tests on Anandtech realistic? I don't run my games at 3000x2000 resolution, but ridiculous tests like that show us what a video card can do. For CPU tests we're looking at Phenom II and Core 2 Quad systems running games at 800x600 and getting 200fps. It's a ridiculous test, but it isolates the hardware being tested.
The methodology in the article, in my opinion, is like testing a bunch of video cards at 800x600. Seeing that every video card is getting 200fps (the CPU bottleneck), the conclusion would be that upgrading the video card is a waste of money. Similarly, testing something that reduces CPU bottlenecking should not be done with a CPU that isn't bottlenecked by any game in existence.
Gannon - Saturday, July 4, 2009 - link
This product has no real market, it's just an excuse to charge more money to clueless among the gaming population.What they should really do with this card is make it multi port and a router, I would love to ditch my piece of shit router that requires constant reboots because of someones Wifi dropping (it works fine for wires connections). If they could build a wireless router network add in card + network stack offloading + opening up the card to developers, then I'm in. Screw the "gaming" portion of it, how bout building a quality product gamers would want?
Such as: Bandwidth control (so users can't flog the connection can have their bandwidth limited so it doesn't fsk_up your ping in an online twitch game like quake 3, etc, etc... othe routers have attempted this like Dlinks "Gamefuel", so one can have torrents + game at the same time, no one has really done it very though.
The networking stack is the least of a gamers worries on a modern computer, there is a reason everything has become more integrated over time (audio + network), with the rise of the internet NOT having an ethernet port on a computer is stupid and most onboard NIC's are so good now-a-days unless you are doing some serious file transferring you don't need it.
Anyone claiming to see a performance benefit is shitting you, the real problem lies in input output latencies to devices, RAM and hard drives.
I'll take audio + NIC integrated on future CPU's with an integrated memory controller over add-in shite that is just going to fade away over the next 5-10 years.
Gannon - Saturday, July 4, 2009 - link
Also the next real major speed up for games is in Solid state disks, what we really need is:-Newer faster Memory technology, CPU spends most of it's time waiting on RAM (and ram is damn fast comparable to hard drives and even solid state drives).
-Newer faster permanent storage (SSDa and beyond)
When solid state disks mature and they finally come out with a chipset that can really take full advantage of SSD's and the bandwidth they offer we'll see a lot more performance improvement.
Try playing a game that chugs on an old hard drive, then put it on an SSD, notice it's not as choppy when things get harry. I noticed this when I moved many of my games from an older 320GB drive to my 1TB drive, games that were slow/choppy suddenly got a speed boost because the drive IO was a sever bottleneck, I can't wait to get an SSD once their capacity expands and price comes down to saner levels.
navilor - Saturday, July 4, 2009 - link
I have on my old machine (a Core2Duo E6600) the Bigfoot KillerNIC M1. I thought that it was a complete crock of [expletive deleted] until a buddy of mine bought one and reported a much better gaming experience.And what exactly did it do?
He played Everquest and it lowered his latency a lot. This means that his character is a lot more responsive to what is happening around him. Yes, you can disable Nagel's algorithm and do something similar, but that wasn't the end of it.
He was able to report being able to run with higher graphical settings enabled. It also removed a stutter that he previously did not notice.
So I sucked it up and decided to blow some cash on that product.
Excellent investment. No longer did my CPU have to manage TCP/IP packets. UDP packets were invisible (via WireShark) yet passed through to the OS without issue (there is a Game setting and an Application setting for those who need it).
This network card offloaded work so my CPU could be used to manage things. Now you might think that my CPU was lame. World of Warcraft, which is the game I play, barely touched the CPU at all. No matter how powerful your CPU is it still has to deal with networking.
Unless it doesn't because you have a KillerNIC.
Now did it lower my latency? No, but it did for my friend. Did disabling Nagel's algorithm help? Yes, but it didn't smooth out my frame rate. Combine the two and you will notice a difference.
On my new rig (Core i7 920 with a GTX 295 and 12GB of RAM) disabling Nagle did jack for me. I am considering either purchasing the new Xeno Pro or possibly stripping the M1 out of my old system. My card can run a firewall on it (iptables) so I don't have to burden Windows with that overhead.
Oh, and high end servers run network cards that do TCP offloading. I'm vaguely certain that those types of cards are there for a reason.
You can prioritize your packets all you want on the network, too. That is always a good first step. What the network cannot do is reduce the time it takes for your application to:
1). Generate a packet
2). Have it go through the windows networking stack
3). Go through the Windows network driver
4). And then out the cable.
The Killer products remove step two and the overhead of step three.
Windows, by default, likes to lump packets together for high speed transmission. See also Nagle's Algorithm. That can be disabled via a few registry hacks. Removing the overhead of Windows compressing those and shoving them through the driver smooths things out. If you have a KillerNIC then you can still manually disable Nagel (which lightens the workload of packet management a small amount) and let the KillerNIC worry about the rest.
So what this means is that the Killer products prioritize the packets INSIDE of your machine BEFORE they hit the home network to then be prioritized on your internet facing router.
DerekWilson - Sunday, July 5, 2009 - link
I get the things that the Killer is doing and that those things are real ...But if your friend took the $120 for the Killer Xeno Pro (or the likely much higher cost of the M1 at the time) and spent it on a faster CPU, the benefits would have extended to much more than just making packet processing faster.
It would have benefited many other applications as well in addition to delivering the performance needed for smooth network play.
has407 - Saturday, July 4, 2009 - link
I won't argue with your experience, as I haven't used one of these NICs. However, is it a cost-effective or appropriate way to solve the problem? Color me skeptical; the evidence is at best inconclusive.1. Nagle applies to TCP, not UDP.
= You aren't going to see any improvement disabling Nagle for apps that use UDP.
2. TPC_NODELAY is a way for apps to bypass Nagle.
= Apps with time-sensitive needs and that use TCP should use it. Nothing you can do about this, but I would hope and expect game developers would be cognizant of it and use it appropriately (or use UDP).
3. An old 2.2GHz Core-2 can drive > 150KBs of 1-byte packets with TCP_NODELAY; > 500KBs using 1-byte UDP packets; > 225MBs with 16KB packets; and peaks at ~300K segments/sec.
= For modern CPU's, CPU time is noise given typical Internet bandwidth.
= Latency/CPU due to the network stack is noise.
4. Some NICs have features which you may want to disable. E.g.:
- Interrupt coalescing. This reduces CPU load by not generating an interrupt for every packet. That may be counterproductive for games.
- Large send offload. Removes the CPU overhead of segmenting large packets into smaller ones and moves it to the NIC. Doubtful there'd be much difference unless the game is sending large packets (which I expect isn't the case).
- Jumbo frames. Don't. In this scenario they're at best a NOP and at worst will degrade performance.
In short, will the Killer NIC perform any better than a properly tuned system? I doubt it. Is the $premium worth the equivalent amount spent on a faster CPU or GPU, or the time required to tune the system? Your call, but again I doubt it.
p.s. No, disabling Nagle does not reduce "the workload of packet management a small amount". It exists to reduce per-packet overhead by coalescing small messages into larger packets.