BVM: Hardware – FAQ

 BVM Ltd have decades of experience in the industrial pc and computer systems business. Over the years, not only have we advanced our wealth of expertise, we have put together the most common questions our customers have about computer hardware, and the solutions for those queries. Let’s take a look at those questions and answers now.

ITX Motherboards:

Q: I have a motherboard which supports both power from an ATX PSU or power from a DC source, but how will I power my HDDs, if use a DC source?
A: When the motherboard is powered by a DC source, the ATX header becomes an output. Check in your accessory kit for a break-out adaptor that provides HDD Molex and SATA from a 20pin ATX plug.

Q: Why is there there’s no display output from my DVI to VGA adaptor?
A: It’s likely that there is no VGA display signal at the DVI port. It could be a DVI-D which has digital display signals only. A DVI-I or a DVI-A have VGA display signals.

Q: What is ‘Display Port’?
A: Display Port contains video, USB and audio signals. You can daisy chain professional quality monitors from a single Display port. For backwards compatibility, you can get passive and active adaptors to directly connect VGA, DVI and HDMI. Some motherboards are fitted with Display Port sockets that allow you to directly connect an HDMI plug into it.

Q: How do I select the correct power supply for my motherboard?
A: You select the power supply that has the correct connector for your motherboard’s power connector header or jack, i.e. 2pin/4pin/20pin/24pin ATX or 2·1mm/2·5mm power jack. Some 24pin ATX motherboards will support the lower 20pin type, but I don’t recommend you exercise that ability when building a new system. Select the power rating of your power supply based upon the system specification as a whole. (See – ‘How do I select the correct power supply for my system?’)

Q: Why are the DIMM slots differently coloured on my ATX motherboard?
A: This is to identify pairs of DIMM sockets for implementing dual channel memory mode. Check the manual for a preferred pair to have memory modules fitted with RAM, when you are only using a single pair of DIMM modules. (See – “What is dual channel mode when referring to RAM configuration?”)


Q: What is dual channel mode when referring to RAM configuration?
A: Dual channel mode is a bit like a RAID stripe array; data is divided between a pair of modules of RAM in alternate stripes. While waiting for a stripe of data to arrive from a data request made at one RAM module, the controller looks over to the other to request the next stripe along. It is a very effective boost in RAM performance. For best results, buy RAM that is sold in matched pairs when implementing this mode.

Q: How do I select the correct RAM module for my motherboard?
A: You will find the maximum supported data rate listed in the datasheet or the manual for your motherboard, such as DDR3-1600 which has a module classification PC3-12800, i.e. 12·8GB/sec. Sometimes a bandwidth of data speed is given for the motherboard; choose the highest for performance, the lowest for economy and lower power consumption. If you have a low-end CPU such as an Intel Core i3, your motherboard won’t use the high speed of 1600MT/s (Millions of) transfers per second.

Q: What’s the difference between DDR3L and DDR3U?
A: DDR3L is low power DDR3. It requires less voltage; 1·35 volts over instead of 1·5 volts for DDR3. DDR3U is even lower power over DDR3L, using just 1·25 volts. The power savings are 15% and 10% respectively.

Q: What is the ideal RAM quantity for 32bit and 64bit operating systems?
A: 32bit operating systems can only use a maximum of 4GB. It is the limit of the 32bit operating system. I recommend a minimum of 2GB. 64bit operating systems can use a maximum of 16EB (ExaBytes), but I recommend 8GB minimum, otherwise, you’re under-using your choice of electing to use the reason for using a 64bit operating system.

Q: Why isn’t Windows using all of my 4GB of physical RAM?
A: Some of the ram is used for mapping and further space is used as integrated graphics memory. You can specify the maximum quantity of RAM used by the integrated graphics in the BIOS.

Q: I have installed 4GB of RAM, but only 2GB is showing as usable. Why?
A: Your motherboard has a maximum supported memory module capability of 2GB capacity. Memory module slots require more physical connections to support higher capacity memory modules – this is an extravagance for embedded motherboards that hold a small foot-print like the pico-ITX or the nano-ITX form factors.


Q: Why is my touch screen is moving the cursor in the opposite X and Y directions?
A: The ribbon tail from your touchscreen is rotated 180°. If that doesn’t cure the issues, you probably need to access the touchscreen controller’s configuration software. Otherwise, you may be using an incompatible controller and will require an adaptor between the ribbon tail and the controller.

Q: Will my PCIe GEN3 card be seen in the BIOS of a GEN2 PCIe slot?
A: Yes. PCIe generations are backwards compatible. Set your PCIe BIOS parameter to Auto.

Q: How do I connect an LCD directly to my motherboard?
A: You need two cable assemblies, one for the display signal called an LVDS and a second to control the backlight. Then you will need to set the motherboard’s BIOS to suit your LCD’s parameters. Connections and BIOS support occurs in nearly all industrial motherboards.

Q: What’s the difference between PROJECTIVE-CAPACITIVE and RESISTIVE touch screens?
A: Resistive touch screens are tactile and can be used wearing gloves. Projective-Capacitive have the sensor behind the substrate glass and support multi-touch and Windows Gestures.

Q: What is WEAR LEVELLING in SSDs and what is TRIM in Windows 7?
A: Wear leveling is the management of wear in the SSD’s flash controller. It avoids writing repeatedly to the same blocks. Windows 7 and onwards is SSD aware and uses the TRIM command to reduce garbage written to the SSD’s flash. As well as delete, TRIM command is also used at the partition and volume-level operations, in formatting, compression and system restore. Don’t defrag your SSDs and don’t fill them beyond 75% capacity.

Q: Why is my LCD brightness dim and the brightness control all wrong?
A: Your LCD parameters in the BIOS are set for the wrong kind of backlight. You have probably got an LED backlight being controlled by a BIOS setting for CCFL backlight control. Or – there could be a jumper which toggles the type of control between LED and CCFL.

A leading designer, manufacturer and supplier of industrial and commercial computer products, BVM Ltd are highly qualified to advise on everything and anything to do with computer hardware. Looking for new computer hardware? BVM distribute their products world-wide, so get in touch today.

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