Will this board work in my server?
When buying a board to fit inside a particular system, there are a number of things to be aware of. It may appear that one PCI board is much like another, but unfortunately there are a lot of variations that can cause complications. Whether you have a specific system in mind, or you are buying a new system as well, this document outlines what you will need to consider:
Physical dimensions - Length
Inside a server, the PC slots are designed either to fit a long board or a short board. A short board will go into either, but a long board requires the full space and usually a channel to slot a board retainer into at the back. To save on space, system manufacturers don't always provide many (or even any) full-length slots. This doesn't usually present a problem, but when dealing with mulit-port boards you may find they require a full length slot
How do I tell?
Check the length of the board on the datasheet. If the length is above 175mm then it is a long board. If your server has a similar sized space in line with the PCI slots, and an edge retainer panel at the back, then the long board should fit. Be careful if you need to ship a system with a long board in it: It needs to fit in the a slot at the back to be securely mounted. Otherwise the rigours of shipping may dislodge or even break the board and other components nearby.
Physical dimensions - Width
The PCI specifications include a maximum height that components can project off a board - keeping everything inside what is known as the 'envelope'. However, board designers are not always able to keep inside those specifications, particularly if they have to mount a fan on the board. Even if you can physically get the board in, it may touch a board in the adjacent slot, leading to shorts, or block the flow of air. This is particularly an issue if the boards generate a lot of heat. The end result is that one board takes up two slots, or won't fit in to a low profile server at all!
How do I tell?
This is slightly more difficult to tell. Check the datasheet to see if the board 'package' is thicker than 20mm. However, datasheets may not always be accurate. Take a look at pictures of the board, and when you install it, make sure it isn't touching any boards or components next to it, and that air can flow freely around it. Also, check the small print in the user documentation to see if there is any information on this subject.
Signalling voltages and PCI connectors
There are several versions of the PCI standard that have been issued over the years. The last couple of releases of the standard have produced a fundamental change to the way the boards talk to the PCI bus: The voltages for signalling have changed from 5V to 3.3V. A board that is compliant with the PCI 3.0 standard will support both voltages. However, PCs and servers available on the market today may only support 3.3V signalling. This means that a board that only supports 5V signalling may not work in a new server.
How do I tell?
Your system documentation should specify the voltages supported, but if it isn't specific but talks about PCI 3.0, PCI 2.3 or PCI 2.2, then you may need to check with the manufacturer if you want to use a 5V board.
Board datasheets should also specify the voltages - look for 'PCI 3.0 compliant' or a similar statement to make sure. If the voltages are wrong, the connector will be subtly different, so the board won't actually fit in your system.
PCI Connectors
The PCI standard has also been updated with new variants like 64bit or 66MHz slots, and a whole new branch called PCI-X. Standard 32bit PCI boards (as most are) will still work in these slots if they have the most recent PCI connector type.
How do I tell?
As with the signalling voltages, you need to look for PCI 3.0 compliance. Boards that conform to an earlier specification, or don't specifically state conformance simply may not fit or work in your system.
Power Draw
Just like the other aspects mentioned here, there are maximum limits on the amount of power an individual board draws from one slot, and this also determines the heat it generates. However, that doesn't mean that a particular server can cope with individual or multiple boards that all draw the maximum power according to the PCI specifications.
The Power Supply Unit (PSU) will have a maximum rating, anywhere between 200W and 500W, but 350W is very common. Each component in the system will eat into that power figure. If you are running multiple boards that draw a lot of power, you can overwhelm the PSU and potentially damage the system.
How do I tell?
Unfortunately, this can be quite complex. Your system documentation should state the PSU size, and may state the maximum 'thermal load' it can deal with. The PSU will almost always have the wattage on a label that you can see if you open up the case and take a look.
Once you get this figure, you can work out the draw from the different components individually, but this could be complicated. A normal server motherboard without expansion cards usually draws up to 300w in operation - this is an indication only, and you shouldn't simply assume that this is the case with your system. The important point is that if you have a 350W PSU, and you have 3 boards pulling 17W, then you are in danger of overloading your system.
Heat Output
The power drawn by the board is converted to heat, which the server has to dissipate. Cooling inside a high performance PC or server is always an issue, and with boards that generate a lot of heat this can have serious consequences. If your server overheats, then boards and other components can become damaged quite easily.
Most power supplies have a thermal fuse that will cut out before the system actually catches fire. However, the system may well reach temperatures high enough to destroy or damage the more sensitive components without you realising it. This must be taken into account, particularly for server systems that run 24x7. A lot of server rooms have air conditioning or ventilation designed to stop excess heat build-up. Firstly the server has to get the heat out where these systems can make a difference, and secondly you want a bit of a margin in case your air conditioning stops working!
As well as the temperature throughout the server, there can be problems with localised high temperatures. The overall heat output may be acceptable, but it could be generated in a very small area. In that case it is important that there is a proper airflow over the board. This is particularly an issue for what is known as 'intelligent' boards that often have very high power components on them. Sometimes these boards will even include a heatsink and fan to maintain operation. In that case, there is not only a heat dissipation issue, but if the fan on the board fails then the board, and boards next to it, are likely to become damaged.
How do I tell?
This is not simple unless all the documentation is clear. The cooling systems in your server may be rated for a maximum heat dissipation (measured in watts usually), in which case you can match that to the heat generation (or power drawn, as they are equivalent).
However, servers do not always specify that figure, in which case you have to be conservative in your estimates. If you can't avoid boards with high heat output, we recommend that you use a system with good thermal monitoring, and stay away from boards with fans if possible. A system with thermal monitoring should have a CPU and internal case temperature sensor that connects in to monitoring software as part of the BIOS or operating system. It should be configurable to give you a warning if the temperature rises too high. Once you are confident that the system temperature maintains itself within acceptable limits, then you can leave it unattended. If the temperature inside the case gets above 50 Degrees Celsius then there may be sensitive components that are considerably hotter, and in danger of getting damaged.
Companies that supply full server solutions can give good advice on cooling and monitoring solutions.
The Simple Answer:
All of these concerns are important for safe operation across a wide range of systems and environments. These are some of the concerns that we have taken into consideration when designing the RockForce range, so that you don't have to.
Compatibility and standardization is somtheing we take very seriously at Mainpine. This is why we actively support activities in the standards bodies, and are on the PCI-SIG Integrators list.
The Mainpine RockForceT multi-port boards for fax, data and voice applications are the only products available that meet all the following requirements:
- 2, 4 or 8 RJ11 Analog ports
- Super G3 V.34 Fax and JBIG compression
- V.92 56kbps data connections, line bonding
- Short board form factor
- Low thermal output (7W maximum)
- Universal PCI (5v and 3.3v)
- PCI 3.0 compliant fitting in ANY PCI or PCI-X slot!
Prices start from $499 MSRP.
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